# PAR vs Distance, T5, T12, PC - New Chart



## killacross

you left our spiral CF bulbs but either way...cant wait to see how this thread will evolve..especially if i4x4 gets involved and you two heavy weights can duke it out...(dont be Roy Jones Hoppy! lol)

thank you for never letting this subject die!


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## Hoppy

Spiral CF bulbs are a different breed of light. The ones on that chart are all linear tubes which tend to produce the same PAR for any length of bulb, with the length to be used depending only on the length of the tank they are to be used over. But, spiral bulbs have varying lengths twisted together to get all of the light emitted over one small area. There is a thread in the stickies that I think covers those bulbs as well as they can be, for now. 

I have enjoyed working with lights since I worked for NASA many years ago, when I was working on a "bulb" that was a water cooled tungsten arc bulb, using argon as the gas flowing through it. Now, that was BRIGHT!


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## killacross

what about the new sulfur-plasma bulbs? Ill have to find a link because I cant remember where I saw it...

they demoed one to show the range of intensities (like 5%-95%) once at the university and we all saw spots for a while

***edit***
http://www.sulphurplasma.com/

really, I find the lighting interesting because its usually the easiest "upgrade" we can make to a tank

but really Im trying to find a way to upgrade the light in my projector from teh standard halogen/xenon/whatever bulbs to a high intensity LED (tho LEDs lack the throw distance :-/- but one day Ill buy 1 $200 bulb thatll last 20years)


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## plantbrain

So 2.9W/gal for 4x 40 W T12's on a 55 gal tank is still lower light than 40micromols........

So around 3W/gal is considered high light by many that use the conversion, then they run out and apply it to a T5 or a PC light set up and *assume they are the same.*

I'm not sure why testing is so horrible for lighting when so many on the forums over the years harass people about the need to test things like NO3 or PO4 critically, or Fe and Mg etc......balancing K+ and all sorts of hoodoo.

Then do not measure light.

CO2 has it's many issues, but light is fairly straight forward and not hard if you use a meter. Hoppy's graphs illustrate the point pretty clearly.

Does not matter what differences tank to tank we might have, with a PAR meter, you have a good idea for comparisons. Quick, easy and lightly(pun intended) do not have to do it again from then on. Cost is the main issue for the PAR meter, some have suggested renting, but many are too cheap even for that, but are willing to spend $$$ for test kits.
You can also buy it, use it, rent amongst local folks, then sell it.

Why would you need it much more unless you are like Hoppy or myself interested in doing comparisons in real or hypothetical cases?

Might as well sell it back for 200$ or so.
If you buy it for 200-240 in a group buy, it cost you next to nothing.

Folks will buy them for the 200$ range pretty easily.

Regards, 
Tom Barr


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## wkndracer

Thanks again Hoppy.


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## sanj

Hello Hoppy,

thanks for doing this test, informative and interesting.


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## shoggoth43

*T5?*

Where do you suppose a T5NO ( normal output like at HD ) would fit in this graph? In theory they put out more light per watt but at less watts than the T5HO I'm not really sure if they'd be nearer the PC graph or below it since I've really got nothing to compare it to.

-
S


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## Hoppy

I haven't tested T5NO lights, nor have I seen any data from anyone else for them. I do know that T5NO lights are more efficient than T5HO - more light per watt - and T5NO lights are a bit more than half the wattage of T5HO lights. So, a T5NO light should produce more than half the light that a T5HO light does, but only if it has the same quality of single bulb reflector. Unfortunately, I don't think any T5NO light does have the same quality reflector. I think the best guess I can make is that a 2 bulb T5NO light will produce about the same PAR as a typical one bulb T5HO light. I suspect it produces less PAR than that.

And, remember, AH Supply PC light fixtures have uniquely great reflectors. Coralife fixtures, for example, don't have nearly as good reflectors. And, many cheap PC light fixtures effectively have no reflector at all, because they allow no room for one. They might produce only half the PAR as an AH Supply light.


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## GTR

So if you had a decent reflector for T-12 what would you guess the increase would be. 

Not sure there's a valid reason to use them anymore but having used them for 25 years it's like losing an old friend. lol

SteveU


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## Hoppy

GTR said:


> So if you had a decent reflector for T-12 what would you guess the increase would be.
> 
> Not sure there's a valid reason to use them anymore but having used them for 25 years it's like losing an old friend. lol
> 
> SteveU


I think you might gain another 30-40% if you used a somewhat parabolic, highly polished aluminum (MIRO 4) reflector, that was big enough for that size bulb. That would barely be a significant increase.


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## speedie408

Great brain food.


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## insta

Hoppy, if I reflectorize my little DIY LED fixture and mail it to you, would you mind running it through this same test?


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## SemperFish

Great information for a planted noob like me. Would you answer a question for me? I plan to step up from a low tech 29 gal to a low tech 55 gal. I'm considering going with either 3x32 watt T-8s or 3x28 watt T-5 NO's. I do plan on doing an occasion excel dose, using eco complete, and low light/hard to kill plants. Would these choices be good lighting for what I want? Suggestions....Thanks in advance.


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## shoggoth43

Well, I've got a Tek5. I was just curious if there might be any reason to retrofit the ballasts and such at some point since the T5NO lights are somewhat easier to find without going to a supply store. I think the reflectors in those are pretty decent.

-
S


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## Hoppy

insta said:


> Hoppy, if I reflectorize my little DIY LED fixture and mail it to you, would you mind running it through this same test?


I wouldn't want too accept the responsibility for getting the light back to you in operating condition. Have you looked for an aquatic plants group near you, like http://www.kcfishclub.org/ That might be a group that has a PAR meter, or one of their members may have one.


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## Hoppy

SemperFish said:


> Great information for a planted noob like me. Would you answer a question for me? I plan to step up from a low tech 29 gal to a low tech 55 gal. I'm considering going with either 3x32 watt T-8s or 3x28 watt T-5 NO's. I do plan on doing an occasion excel dose, using eco complete, and low light/hard to kill plants. Would these choices be good lighting for what I want? Suggestions....Thanks in advance.


3 T8 bulbs on a 55 gallon tank, 20 inches high, or 1 T5NO bulb, should give you low light. Or 2 T5NO bulbs should give medium light. Of course if you choose to hang your light above the top of the tank, which I think is the best way to light a tank, you could use even a single T5HO light - hanging 4-5 inches above the top of the tank, to get low medium light. That gives you the best uniformity of light in the tank.


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## Nate McFin

Great info Hoppy. 
I am not sure if I should start another thread or use this one but I am starting a 40 breeder tank. 17" Tall with a 3" or so substrate (flourite black). Lights are Catalina 3x39 T5ho ( I will most likely only use the two outer bulbs)
I will have pressurized Co2 and will be dosing EI. I plan on having a carpet (undecided between UG or HC) Stems in the back (Rotalas? Etc.)
I have flip legs for the lights but it seems hanging would be better according to the graph. if I am reading correctly (for the upper end of medium to low end of high light) I should hang the fixture 25 or so inches from the substrate. Is this right? Given my goals would you change anything regarding the set up? Change the number of bulbs used and/or the height? I really dont want algaefest 2010.
I hope you can shed some "light" on the subject, so to speak. 
Thanks,
Nate


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## S&KGray

25 inches above the substrate (11 inches above the top of the tank) looks about right to get 80 micromols of PAR at the substrate using 2 bulbs in your Catalina 3x39 T5HO fixture.


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## SemperFish

Hoppy said:


> 3 T8 bulbs on a 55 gallon tank, 20 inches high, or 1 T5NO bulb, should give you low light. Or 2 T5NO bulbs should give medium light. Of course if you choose to hang your light above the top of the tank, which I think is the best way to light a tank, you could use even a single T5HO light - hanging 4-5 inches above the top of the tank, to get low medium light. That gives you the best uniformity of light in the tank.


I appreciate the response. Thanks for the great info. I think I will go with the T-5 NO set up.


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## doinkmobb

Hoppy said:


> I have been wondering how much PAR a typical T12 light produces. Like most everyone else I have just assumed that watts per gallon was a way to guess the light from T12 bulbs, but there is no more reason to expect that to mean anything than there is to expect it to mean anything for other bulb types. So, I decided to do some testing.
> 
> I borrowed a new two bulb 48 inch T12 light fixture from one of our local aquatic plant club members, bought a new T12 bulb - a Phillips "Natural Sunshine", 40 watt 5000K, 92 CRI bulb at HD, borrowed our club PAR meter and took some readings.


So you put one bulb in a two-bulb fixture?

I have two-bulb T12 shop lights, and when I install only one bulb, it lights up very dimly until I pop in the other bulb. Did you ever install a second bulb to see if there was a change in brightness?

I wonder if this could have given you incorrect data...


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## Hoppy

doinkmobb said:


> So you put one bulb in a two-bulb fixture?
> 
> I have two-bulb T12 shop lights, and when I install only one bulb, it lights up very dimly until I pop in the other bulb. Did you ever install a second bulb to see if there was a change in brightness?
> 
> I wonder if this could have given you incorrect data...


I didn't try two bulbs because I didn't want to pay for two. But, the bulb lit up as brightly as I usually see, anything but dimly. I don't recall any previous magnetic ballasted T12 fixture I have used doing what you saw, but I don't rule it out. The fixture had two power cords, two switches, so I assumed it was intended to run one bulb alone if desired.


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## doinkmobb

Hoppy said:


> I didn't try two bulbs because I didn't want to pay for two. But, the bulb lit up as brightly as I usually see, anything but dimly. I don't recall any previous magnetic ballasted T12 fixture I have used doing what you saw, but I don't rule it out. The fixture had two power cords, two switches, so I assumed it was intended to run one bulb alone if desired.


Ah. OK. My fixture has only one power cord and no switches - it lights up when it's plugged in.

I have 4 T12 bulbs 20" above the substrate, with mylar film affixed behind the bulbs acting as crudely designed refelctors. Light output is up over the white reflectors, and heat build up under the canopy is down. The mylar is better, but I really don't know how much better.


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## xmas_one

doinkmobb said:


> So you put one bulb in a two-bulb fixture?
> 
> I have two-bulb T12 shop lights, and when I install only one bulb, it lights up very dimly until I pop in the other bulb. Did you ever install a second bulb to see if there was a change in brightness?
> 
> I wonder if this could have given you incorrect data...


That's been my experience too. I was wondering with the t12 was sooo much lower than the pc and t5.


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## Hoppy

I did some experimenting with mylar, aluminum foil, and ordinary white paint as reflectors. To my surprise, the mylar was the least effective, the aluminum foil the most effective, but just barely better than white paint. I didn't use any special white paint, just what I had in a spray can at the time. I believe if you take care to get an ultra white paint you will get better results with that than with aluminum foil, and certainly better than with mylar. The differences I found were around 15-20% from best to worst, so the light doesn't look much different, but a PAR meter shows the differences.


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## Hoppy

Today, I went back over the data I received from others about various types of bulbs and fixtures, and realized that I could characterize non-AHS PC lights as well as the AHS lights, and that I had one data point for a 150 watt HQI fixture. So, I added that to my chart of PAR vs distance, double checking how I derived that chart. It changed a little, on double checking, but not significantly. Of course the HQI line is just there for comparison, it isn't nearly good enough to use for selecting that type of fixture. The other lines should be good enough to get you into the low, medium or high light categories pretty reliably.









EDIT:
Another way to use this is to convert it into a simple table, that lets you select a lighting option based on tank height, how high you want the light to be above the top of that tank, and how much light you want. This assumes that multiple bulbs are mounted close together, reflectors are typical for that particular type of light. And, I left out the AH Supply light kits.


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## Minsc

In case I haven't said it before, thank you so much for this thread Hoppy!


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## madhatter4

Great work Hoppy!

How would you compare a single 2X overdriven 32W T8 bulb with a single normal T5NO bulb using an icecap reflector?

I have read a lot about T8/T12 vs T5HO but found little info on overdriven T8 vs anything.


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## S&KGray

madhatter4 said:


> I have read a lot about T8/T12 vs T5HO but found little info on overdriven T8 vs anything.


ODNO T8 output increases over normal T8 (from GulfCoastAquarian's ODNO thread):



2xODNO (2 power leads per bulb) - ~50% increase
3xODNO (3 power leads per bulb) - ~75% increase
4xODNO (4 power leads per bulb) - ~100% increase


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## madhatter4

So assuming 1 [email protected]" gives ~10par, 1 T8ODNO 2X would yield ~20par. If I also assume that 1 T5NO gives about half the par of T5HO, I would get [email protected]" for T5NO.

The T5NO would yield ~10par more over the T8ODNO, that's not a lot but it gets onto the low light range(barley) for 20" depth.

Does this sound right?


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## S&KGray

madhatter4 said:


> So assuming 1 [email protected]" gives ~10par, 1 T8ODNO 2X would yield ~20par. If I also assume that 1 T5NO gives about half the par of T5HO, I would get [email protected]" for T5NO.
> 
> The T5NO would yield ~10par more over the T8ODNO, that's not a lot but it gets onto the low light range(barley) for 20" depth.
> 
> Does this sound right?


If 1 [email protected]" is ~10par, 1 T8ODNO 2x would yield ~15par, 3x would yield ~17.5par, 4x would yield ~20par


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## Oreo

What's the conversion factor from LUX to PAR? I understand it would't be exact because of what PAR and LUX are and that different bulbs perform differently throughout the spectrum. Still, it would be useful information to have a ball-park idea of how the two compare from an average bulb.


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## madhatter4

S&KGray said:


> If 1 [email protected]" is ~10par, 1 T8ODNO 2x would yield ~15par, 3x would yield ~17.5par, 4x would yield ~20par



Haha... that's embarrassing :tongue:, thanks for the correction. not sure why I did that.

So that would put a T5NO at about twice the intensity of a 2XOD T8. That's enough to warrant an upgrade I think.


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## Hoppy

Oreo said:


> What's the conversion factor from LUX to PAR? I understand it would't be exact because of what PAR and LUX are and that different bulbs perform differently throughout the spectrum. Still, it would be useful information to have a ball-park idea of how the two compare from an average bulb.


I haven't tried to determine the answer to that. Most bulb manufacturers don't print the LUX @ X inches rating on their bulb packages, so I never felt it was an important thing to know. I do know that the conversion factor would be much different for a GE9325K bulb, a 6500K cool white bulb, a 10,000K bulb, etc. How much different I don't know either. Someone else can have the fun of figuring this out:smile:

T5NO lights are interesting. I read a few years ago that the efficiency for converting watts to light for a T5NO bulb is higher than for a T5HO bulb. And, I know that for any given length bulb, T5NO bulbs are a little more than half the wattage of T5HO bulbs. From that you could assume that a 2 bulb fixture with T5NO bulbs would produce about the same or a little more PAR than a one bulb T5HO fixture. *Except*, that few T5NO fixtures use reflectors that are nearly as good as typical T5HO fixtures. And, the reflector accounts for a big percentage of the efficiency of T5 bulbs. Until someone gets several PAR meter reading for a few different T5NO fixtures I don't know how we will ever know how to judge those fixtures.


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## fishyjoe24

tom and hoppy where do you think my 192w (2x96w) power compact bulbs stand in the line of par now that they are over 2-20H tanks with the lights beening 18-20 from the substrate, oh and I also have c02 now just need to get the bottle filled and recert.


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## madhatter4

Hoppy said:


> T5NO lights are interesting. I read a few years ago that the efficiency for converting watts to light for a T5NO bulb is higher than for a T5HO bulb. And, I know that for any given length bulb, T5NO bulbs are a little more than half the wattage of T5HO bulbs. From that you could assume that a 2 bulb fixture with T5NO bulbs would produce about the same or a little more PAR than a one bulb T5HO fixture. *Except*, that few T5NO fixtures use reflectors that are nearly as good as typical T5HO fixtures. And, the reflector accounts for a big percentage of the efficiency of T5 bulbs. Until someone gets several PAR meter reading for a few different T5NO fixtures I don't know how we will ever know how to judge those fixtures.


As far as reflectors go, a single bulb icecap reflector is no different on a T5HO then a T5NO right? Any upgrading I do will be a retrofit into my hood rather then a T5NO fixture.


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## Minsc

Looking at a Coralife T5NO 2 bulb fixture, it looks as if maybe a third of the light being produced by each bulb is making it into the tank. The reflector design is just that bad.

So, it would probably take 2-3 fixtures, of 2 bulbs each, to equal the light from a single T5HO with a quality reflector.


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## Hoppy

fishyjoe24 said:


> tom and hoppy where do you think my 192w (2x96w) power compact bulbs stand in the line of par now that they are over 2-20H tanks with the lights beening 18-20 from the substrate, oh and I also have c02 now just need to get the bottle filled and recert.


Those tanks are 24 inches long, right? And, they are end to end, or 48 inches total length? With a pair of 35 inch long lights sitting on the top of the tanks? Assuming that is all correct, the half of each tank directly under the pair of bulbs, which have to be close together, given the 12 inch depth of the tanks, would be about twice what one bulb would give.

The big unknown is whether these are like AH Supply light kits, or like Coralife light fixtures. If like AH Supply, the PAR would be around 100 micromols of PAR, but if like Coralife, it would be more like 40 micromols of PAR. At the end of each tank not directly under the bulbs, the intensity would be quite a bit less.


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## Oreo

Anybody here feel like lending / renting me a PAR meter? If so I'll take readings of a 10,000k T5HO and a 6700k T5HO at various heights in both PAR and in LUX and post the results. (Such a simple thing but no one has done this yet.)


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## Hoppy

I just edited the chart here, http://www.plantedtank.net/forums/lighting/105774-par-vs-distance-t5-t12-pc-2.html#post1093075 to add a table that might make it easier to use.


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## barbarossa4122

Hi,

According to your chart I have high light. Thanks for the info Hoppy.


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## Nate McFin

Why is this not a sticky yet???:confused1:


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## reybie

Thanks to the charts I can now confirm that I was sunburning my plants and fish :icon_cool

I shut down 2 of the T5HOs and will continue with just 2 now and those alone would give me ~100 micromols at my current height of 23" from substrate.


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## ballen

Ok im newer to planted tanks and trying to learn as much as i can as i slowly build up my 75g tanks. Right now i am trying to figgure out my lighting needs. So here is my question with only being able to get t5no lights at 2x28watts how many would i need to buy to put me at the higher end low to low mid mid light range if my substrate will be at about 20 to 22in from my light with basic reflection ie white paint as the min but more likly Aluminium coil stock lind custom hood. I know that i should try for a better light scorce but because of where i live and cash flow it has limited me in what i can buy at this time.


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## S&KGray

You should be fine with one 2x28 per tank to get low to med light

Edit: i meant with a good reflector, see Hoppy's comments below


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## Hoppy

ballen said:


> Ok im newer to planted tanks and trying to learn as much as i can as i slowly build up my 75g tanks. Right now i am trying to figgure out my lighting needs. So here is my question with only being able to get t5no lights at 2x28watts how many would i need to buy to put me at the higher end low to low mid mid light range if my substrate will be at about 20 to 22in from my light with basic reflection ie white paint as the min but more likly Aluminium coil stock lind custom hood. I know that i should try for a better light scorce but because of where i live and cash flow it has limited me in what i can buy at this time.


That is actually a difficult question to answer. Those charts for T5 are based on the light you get with typical T5 highly polished aluminum reflectors. You can make a lot of assumptions about what percentage of the light comes from reflection off the really good reflectors, and use that to guess at how much PAR you would get without any reflector, then add maybe 10-20% more for the white painted, but flat reflective surface. What you would end up with would be very inaccurate, and probably worthless.

Or, since 28 watt T5NO bulbs are about 48 inches long, you can assume they produce the same light as a T8 48 inch bulb, but use less electricity to do so. That is probably a better guess. Then I would assume they produce perhaps 20% more light than that due to the smaller tube size, giving what should be a brighter light. Doing that, my guess is that 2-28 watt T5NO bulbs at 20 -22 inches with a flat white reflector would give you low light, just barely within the range for low light. Using aluminum foil instead of white paint would slightly increase the amount of light, because white paint is a very good reflector surface, almost as good as aluminum foil. But, it would be worth doing since it might be enough improvement to get the light intensity well within the low light range.

You could further improve this by using a curved reflector surface that surrounds the tubes on 3 sides - like a section of rain gutter, for example. Then line that with aluminum foil. I doubt that this would get you to medium light, but it might.


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## ballen

i am able to get coil stock that his polished aluminum like the kind that people would use around a chimney for the rain pan . The type i can get comes in from 14 to 20in wide by 10 ft long. i have done some construction and i am use to having to bent it at slight angles and even to curv it. i could curve a piece behind the lights as a makeshift relflector. I am planning to get more of the 2 set lights atleast 2 more so that wold put my at 3x28wttsx2 or about 160 watts over my 75 g aquarium and that woud put me at about 2.3 wpg i know that wpg is not a good mesurement to go buy buy.


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## milesm

sticky worthy. nice work hoppy.


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## hoa101

You might want to move the figures on Page 2 onto the first post, Hoppy. I like that graph better than the first one. Would be good for newer people, since they will prob look at the first post for sure.

Seriously though, when I read these threads, it was like a revelation for me. The amount of lighting misinformation out there staggers the mind. When I was new to the hobby, people had me convinced I needed like 4 wpg. Of course I ran out and bought a high-powered T5HO fixture and plopped it directly over my 16"-tall tank.

I wonder how many people are driven out of this hobby due to following such bad advice, as they watch their entire tank become a mess of algae? We need more people like Hoppy!


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## Hoppy

Thank you all! I will see if I can move the charts to page one.


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## reybie

It's true how much money people could have saved if information like this was available in the beginning. I myself bought a 4 bulb fixture when I could have gotten away with a 2 bulb setup.


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## Chucklett

Im a newbie and dont have a very scientific mind, but your chart was very easy to understand Hoppy - thankyou! Apparantly, I have no light in my tank :icon_eek: 

My water depth is about 20" and I have 2 x T8 (30w each) lights fitted to the underside of the hood. Im not too worried about this - my fish are happy and the plants are growing.

My question is where do LEDs come into all this? Im planning on getting another tank after the New Year (approx 120cm wide x 40cm deep x 50cm high) and I love the "shimmer" effect you get from LEDs. I also understand that LEDs are more intense than T5s so I should have better plant growth. I plan on four TMC GroBeams (two at the front so they cover the full length of the tank, then the same again at the back).

Any comments or opinions???

Thanks.


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## Kunsthure

I found this thread to be very helpful--and money saving! Now I know that I only need 2x54w T5HO bulbs for my 75g to be the high light tank I want. :biggrin:

Do you think it's just a marketing ploy to make the 4, 6, or 8 bulb T5HO fixtures? 

-Lisa


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## The Plantman

Very good information. Thanks Hoppy!


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## Hoppy

Kunsthure said:


> I found this thread to be very helpful--and money saving! Now I know that I only need 2x54w T5HO bulbs for my 75g to be the high light tank I want. :biggrin:
> 
> Do you think it's just a marketing ploy to make the 4, 6, or 8 bulb T5HO fixtures?
> 
> -Lisa


T5HO fixtures are usually made for reef tanks, where a lot more light is used. That market is a lot bigger than the planted tank market, too. So, manufacturers make lights that are appropriate for reef tanks, with multiple bulbs, actinic bulbs, 12000K color temperature bulbs, etc. Only occasionally do you see fixtures made just for planted tanks, and they almost always have only 2 bulbs.


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## barbarossa4122

Hi Hoppy,

Do you think I'll be OK with my 2 bulbs t5ho raised 30" above substrate ? No co2, just excel......... very heavy planted tank since yesterday


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## Hoppy

barbarossa4122 said:


> Hi Hoppy,
> 
> Do you think I'll be OK with my 2 bulbs t5ho raised 30" above substrate ? No co2, just excel......... very heavy planted tank since yesterday


Yes, that should work very well.


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## barbarossa4122

Hoppy said:


> Yes, that should work very well.


Thanks a lot Hoppy. You and your charts are the one that open my eyes about FW aquarium lighting


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## Chucklett

Hi Hoppy,

Not sure if you missed my question? 

Was wondering how LEDs compare with the other lights you mention?

In particular, TMC GroBeams?

Many thanks :icon_smil


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## Hoppy

Chucklett said:


> Hi Hoppy,
> 
> Not sure if you missed my question?
> 
> Was wondering how LEDs compare with the other lights you mention?
> 
> In particular, TMC GroBeams?
> 
> Many thanks :icon_smil


Sorry, I just forgot to come back to it.

LEDs aren't like other lights. For one thing a single LED doesn't produce enough light to work on any but the small nano tanks. So, you always need to use an array of LEDs to do a good job lighting a planted tank. For the moment, this, http://www.plantedtank.net/forums/diy/84212-designing-building-led-fixture-22.html#post1102937 is the best I can come up with for picking LED lights. And, so far I haven't seen an LED light fixture that I think is a good planted tank light, so to use LEDs you have to DIY one.

That GroBeam 1000 version is only about 8 inches square, so it is probably only effective on a 12 inch maximum depth (front to back) tank, and a 55 gallon tank, for example would need about 5 of them. I don't know what they cost, but I suspect 5 of them would empty most of our hobby budgets. Price has always been the problem with LED fixtures.


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## Chucklett

Thanks Hoppy.

Um, I actually meant the GroBeam 500 (LED strips - approx 47cm long) Sorry :icon_redf 

These are the lights: http://www.tmc-ltd.co.uk/planted-tank/grobeam-500.asp

And the Mounting System: http://tmc-ltd.co.uk/aquarium/aquaray-modular.asp

You can buy T5 or T8 End Caps that fit into the ends of the mounting rail so that the rail slots into a normal T5 or T8 fitting :smile: 

Arcadia have just brought out an LED strip light that, again, you can buy T8 End Caps which fit straight onto the end of the tube http://arcadia-uk.info/product.php?pid=92&mid=11&id=4&lan=en However, I have heard that these lights get considerably hot :icon_frow


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## Hoppy

I only looked at the panel light variety instead of the strips, because I fell very strongly that LEDs should be used in an array that covers most of the top of the tank. If you use strips of LEDs they should be close enough together so you effectively have a panel of LEDs. (Just my opinion.)


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## Chucklett

OK. thanks for your thoughts Hoppy. Very much appreciated.

Your opinion makes sense as LEDs are a direct light source, so logic dictates that you would need almost a "net" of LEDs to cover the surface area of water.

I will continue to research my options of how to obtain the shimmer effect and lush plant growth whilst keeping everything under the hood.

Thanks again :smile:


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## nicholas542

So from the info on the chart my dual 17W T8 isn't really supplying any sufficent light to my plants. It sits about 17" from the substrate level is this correct ?


----------



## Hoppy

nicholas542 said:


> So from the info on the chart my dual 17W T8 isn't really supplying any sufficent light to my plants. It sits about 17" from the substrate level is this correct ?


It might barely give enough light for Anubias, ferns and mosses. Those are good lights for a typical 12 inch high tank.


----------



## nicholas542

ok i'm unplugging the T8's and am going to elevate the T5's a little. I plan on running them for 6 hours a day. does that sound like a good setup ?


----------



## astrosag

I beginning to think that the LFS owner, when he said it was enough, was bs-ing me.

I have a 20G tall (or high) that is approximately 18 inches tall. I have a Jebo 24" fixture with two power compact 24W bulbs. The two options I have to mount it would raise the bottom of the light fixture anywhere from 3 to 6 inches off the top of the water.

Will this do for HC, Dwarf Riccia and Java Moss?


----------



## Hoppy

astrosag said:


> I beginning to think that the LFS owner, when he said it was enough, was bs-ing me.
> 
> I have a 20G tall (or high) that is approximately 18 inches tall. I have a Jebo 24" fixture with two power compact 24W bulbs. The two options I have to mount it would raise the bottom of the light fixture anywhere from 3 to 6 inches off the top of the water.
> 
> Will this do for HC, Dwarf Riccia and Java Moss?


I don't know of any 24 watt PC bulbs, other than UV bulbs. Are you sure they aren't 65 watt bulbs?


----------



## fishyjoe24

so according to your data, I have high light then? am I right... my power compacts started to die out......... so I replaced with t5 ho. but they are only 36inch bulbs. 2x39w with single hagen glo reflectors, and a hagen glo 2x39w ballast on a 55g. I also have c02 but not sure I hooked it up right.


----------



## astrosag

Hoppy said:


> I don't know of any 24 watt PC bulbs, other than UV bulbs. Are you sure they aren't 65 watt bulbs?


Hey Hoppy, thanks for your reply. 

Here's a link to the type of bulbs I have. 

http://www.aquariumguys.com/esu-compact-lamp-24w.html

I need to check the Jebo fixture that the bulbs came with (its at my GFs house) but I'm pretty sure that one bulb burns at 10,000K and the other much lower around 6500K (the LFS insisted that I needed at least one 6500K bulb for plants - which is correct).
Thanks for your eval Hoppy!


----------



## wet

Hi Hoppy.

Do you happen to have the measurements and your values for PAR vs bulb type handy? I mean the raw data before your great work normalizing it as low, medium, high, and too high light. 

Thank you!


----------



## astrosag

Where did Hoppy go?!


----------



## Hoppy

astrosag said:


> Where did Hoppy go?!


I'm still here!

Wet: My charts are based on odds and ends of data, some that I got from my tanks and lights, some from other tanks and lights. I don't have that data in any tabulated form, since this stuff grew gradually over the past 2 years.

Astrosag: I find it very hard to guess how much light a typical PC bulb will give. Most of the data I have is from my own AH Supply lights, which are much, much better than typical PC fixtures, which often have almost no reflectors. So, the best I can do is say that your 2 24 watt PC bulbs should give you from low to low medium light. This could be enough for HC if you also have good CO2, but not otherwise. And, color temperature is largely a matter of what looks good to you. 6500K works, and 10,000K works, but 10,000K bulbs that I have used tend to wash out some fish and plant colors.


----------



## astrosag

Hoppy said:


> I'm still here!
> 
> Wet: My charts are based on odds and ends of data, some that I got from my tanks and lights, some from other tanks and lights. I don't have that data in any tabulated form, since this stuff grew gradually over the past 2 years.
> 
> Astrosag: I find it very hard to guess how much light a typical PC bulb will give. Most of the data I have is from my own AH Supply lights, which are much, much better than typical PC fixtures, which often have almost no reflectors. So, the best I can do is say that your 2 24 watt PC bulbs should give you from low to low medium light. This could be enough for HC if you also have good CO2, but not otherwise. And, color temperature is largely a matter of what looks good to you. 6500K works, and 10,000K works, but 10,000K bulbs that I have used tend to wash out some fish and plant colors.



Hoppy, thanks for your reply!

Well the housing is a Jebo 24" with what I believe are 13" PC bulbs. It has a nice reflector (although nice is very...well..unscientific). The reflector is much better (both mechanically and reflectively) than the original housing for the bow front (Odyssea B20 bow front) had.

I did spend $69 on the unit. So my last question is, for a roughly 16G tank (bow front) at 18" deep (so 15-16" of water), is there a light fixture that you recommend for roughly the same price (~ $70)? 

Its a tall order, I understand. But nonetheless, I would really appreciate the help!


----------



## Hoppy

No, I can't recommend any specific light fixture. I know Catalina fixtures have a good reputation.


----------



## astrosag

Fair enough. Thanks Hoppy 

I'll look into it.


----------



## wet

Hoppy,

Thanks. I figured as much, but since I've not paid proper homage on a forum before, I don't think, let me say this here:

I'm been thinking of leveraging your, SFBAAPS, GerryD and Plantbrain's forum, and the like's PAR vs bulb type vs height data into a free and fast web calculator, where the bonus vs your awesome work here is quantifying those tanks in the margins between, say, medium and high light, but I realize that your work is the definitive calc for this part of the hobby because it raises a finger to the margins and instead acknowledges assumptions and suggests we just adjust height based on the tank we want, be it a low growth long term tank or a fun, challenging, and dynamic high light tank. So: kudos, Guru. Amazing work, as always.


----------



## Hoppy

Thank you Wet! It's always nice to be appreciated. :icon_redf


----------



## Brhino

Thank you for this thread. I hope you don't mind me registering just to ask some questions.

I'm working on a 75g that will be planted with "beginner" type low/medium light plants. I had planned to use 2 dual-T8 shop lights but it occurred to me that they don't have reflectors so I set out to do more research and found this thread. My questions:

If I am reading the graph right, A dual-T5NO fixture will actually be significantly more effective than two dual-T8 fixtures, correct?

I see that the figures given are for the area directly under the bulbs. Given that a 75g tank is a fairly wide 18", will 2 T5NO bulbs put me comfortably in the low-to-medium light range throughout the tank, or should i be spending more money for two dual-T5NO fixtures or perhaps a single dual-T5HO fixture? The fixture(s) will be mounted to the inside of the canopy, so I figure the bulbs will be 2" or so above the top of the tank.

Thanks!


----------



## outcast

wow thank you for this hoppy, that chart is indeed helpful. My next tank will move away from twister CFLs so linear tubes would have been uncharted territory from my personal experience


----------



## Mr BrownThumb

*Too much light?*

Hey Hoppy...
Wow! After reading this chart/thread, I was wondering, could I possibly have too much light? The approximate PAR output is 60 with the high light threshhold at 75 for T5HO 20" from light source. I have 3 x 39w T5HO. Doesn't that put me way above the high light range? I'm thinking of reducing my photoperiod due to a recent algae problem, specifically GDA and Rhizoclonium. I don't think CO2 is the issue, my drop checker turns yellowish green. (I'm still trying to tweak the flowrate down to get it green). Any thoughts on this? Just trying to get to the root of the problem. TIA

Tech specs:
Tank - 36" x 20" x 20"
EI dosing 
Excel 3 x week 
Eheim 2217
2" substrate depth 
Aqueon ACP 950gph
Rex Grigg reactor
Pressurized CO2 on 2hrs prior to photoperiod
Catalina T5HO 3 x 39w on 8 hrs

I did a 3 day blackout/50% water change/Excel dosing to battle it. I'm just trying to prevent a repeat bloom. 

PS: MODS- Let me know if this post belongs in the Algae forum


----------



## Jeff5614

Mr BrownThumb said:


> Hey Hoppy...
> Wow! After reading this chart/thread, I was wondering, could I possibly have too much light? The approximate PAR output is 60 with the high light threshhold at 75 for T5HO 20" from light source. I have 3 x 39w T5HO. Doesn't that put me way above the high light range? I'm thinking of reducing my photoperiod due to a recent algae problem, specifically GDA and Rhizoclonium. I don't think CO2 is the issue, my drop checker turns yellowish green. (I'm still trying to tweak the flowrate down to get it green). Any thoughts on this? Just trying to get to the root of the problem. TIA
> 
> Tech specs:
> Tank - 36" x 20" x 20"
> EI dosing
> Excel 3 x week
> Eheim 2217
> 2" substrate depth
> Aqueon ACP 950gph
> Rex Grigg reactor
> Pressurized CO2 on 2hrs prior to photoperiod
> Catalina T5HO 3 x 39w on 8 hrs
> 
> I did a 3 day blackout/50% water change/Excel dosing to battle it. I'm just trying to prevent a repeat bloom.
> 
> PS: MODS- Let me know if this post belongs in the Algae forum


If you look at the chart, 3 bulbs puts you in the "too high" category. One of your T5HO bulbs at 20 inches from the substrate puts you at 60 par so three bulbs puts you at 180. You may have so much light that you can't provide enough CO2 without killing your fish. Try cutting down to 2 bulbs and/or raising your fixture some if possible.


----------



## Mr BrownThumb

Jeff5614 said:


> If you look at the chart, 3 bulbs puts you in the "too high" category. One of your T5HO bulbs at 20 inches from the substrate puts you at 60 par so three bulbs puts you at 180.


Right. Exactly my point. I cut my photoperiod from 8 hrs to 6 hrs. There is a separate power supply/switch for the center bulb (10000K) so now I'm just running the 2 6500Ks. Raising the fixture is not an option at this point.


----------



## Hoppy

Brhino said:


> Thank you for this thread. I hope you don't mind me registering just to ask some questions.
> 
> I'm working on a 75g that will be planted with "beginner" type low/medium light plants. I had planned to use 2 dual-T8 shop lights but it occurred to me that they don't have reflectors so I set out to do more research and found this thread. My questions:
> 
> If I am reading the graph right, A dual-T5NO fixture will actually be significantly more effective than two dual-T8 fixtures, correct?
> 
> I see that the figures given are for the area directly under the bulbs. Given that a 75g tank is a fairly wide 18", will 2 T5NO bulbs put me comfortably in the low-to-medium light range throughout the tank, or should i be spending more money for two dual-T5NO fixtures or perhaps a single dual-T5HO fixture? The fixture(s) will be mounted to the inside of the canopy, so I figure the bulbs will be 2" or so above the top of the tank.
> 
> Thanks!


Shop lights don't usually have good reflectors, in fact they usually have virtually non-existent reflectors. That prevents you from getting all of the light from the T8 bulbs into the tank. T5NO fixtures usually have reflectors, not necessarily great ones, but at least good enough to get more of the light directed into the tank. So, yes, T5NO fixtures are much better than shoplights. An 18 inch front to back depth by 20 inch deep tank really needs more than one light fixture, if the bulbs are close together as they almost always are. Using a pair of 2 bulb T5NO fixtures widely separated on top of the tank should give you medium light or low medium light if mounted 2 inches above the top of the tank.

But, don't forget, if you want to know with any accuracy, how much light you are getting you have to use a PAR meter and measure the light.


----------



## DANIELSON

Ok i have an odd question. I have a 46G bowfront tank and setting up a mountain scape on the mountain i want to have a high light ground cover plant. On the bottom i want a med type ground cover plant. Can i put a double bulb coralife T5NO fixture 42W to put me at high lighting on the mountain and med on the lower substrate? I see the chart but not too sure how the Watts come into play also?


----------



## Hoppy

Watts just tell you whether the light is HO or NO. The 2 bulb T5NO fixture should give you medium llght at 21 inches, and high light at about 17 inches. You really need CO2 to be able to avoid algae (BBA) on the areas that are close to the light.


----------



## offpath

Hi Hoppy,

I'm trying to use your data to model the expected PAR measurements at various points in my 72x24x30 tank with various potential lighting combinations. I realize that your measurements are for directly below the light, but I was wondering if you had any data/intuition about points not directly below the light.

I know to account for the added distance from the light, but is there any additional falloff from the reflector sending a higher portion of the light directly down or anything? Or do reflectors do a good job of spreading the light evenly through the affected arc? Is 30 degrees a good estimate for the angle of that arc?

Thanks!


----------



## inkslinger

So Hoppy on your chart for 1 pair of t5 54w > Tank is 24 inches high an the lights set 4 inches above that is consider medium and 2 pairs of t5 54w's is 
too high?

My tank is a 110g tank 60x18x24 I have 3 pair's of t5 54w's , I should run 1 pair ea. for 3hr = 9hr? or run 1 pair 4 hr , 2 pair for 1 hr an back to 1 pair 4 hr?
What do you think?

I'm going to try to grow HC plant in my tank an got fig. out how much light I need to get good growth, my co2 will be on with my light cycle ?


----------



## Hoppy

offpath said:


> Hi Hoppy,
> 
> I'm trying to use your data to model the expected PAR measurements at various points in my 72x24x30 tank with various potential lighting combinations. I realize that your measurements are for directly below the light, but I was wondering if you had any data/intuition about points not directly below the light.
> 
> I know to account for the added distance from the light, but is there any additional falloff from the reflector sending a higher portion of the light directly down or anything? Or do reflectors do a good job of spreading the light evenly through the affected arc? Is 30 degrees a good estimate for the angle of that arc?
> 
> Thanks!


Reflectors for fluorescent bulbs are very imperfect. They reflect most of the bulb's light into the tank, but that light is spread out a lot. It takes a point or line source of light to get a reflector to be near perfect (or a very large reflector). The intensity at various points in the tank depends on distance from the light, how close to the glass sides it is, and how big an angle from the vertical it is. I haven't cared to try to figure out what the actual distribution is, but I have made some PAR meter measurements at a few spots. From that I found that the water increases the intensity compared to an empty tank, the reflected light from the glass sides increases the intensity near those sides to at least as high as it is directly under the light, and the intensity does vary approximately with the square of the distance from the light. Also, for the configurations I was testing, the variation in intensity at the substrate level was much less than I expected.


----------



## Hoppy

inkslinger said:


> So Hoppy on your chart for 1 pair of t5 54w > Tank is 24 inches high an the lights set 4 inches above that is consider medium and 2 pairs of t5 54w's is
> too high?
> 
> My tank is a 110g tank 60x18x24 I have 3 pair's of t5 54w's , I should run 1 pair ea. for 3hr = 9hr? or run 1 pair 4 hr , 2 pair for 1 hr an back to 1 pair 4 hr?
> What do you think?
> 
> I'm going to try to grow HC plant in my tank an got fig. out how much light I need to get good growth, my co2 will be on with my light cycle ?


Two pairs of T5HO would be much more light than is easily managed on a planted tank - too high, in other words. If I had your tank I would remove one of the three pairs of lights, or never turn them on. I would consider trying it with one pair near the front of the tank and the other near the back of the tank, hoping that would give reasonable uniformity in light at the substrate level, and knowing it might be too much light. If this is a single 6 bulb fixture I think I would try to rewire it so I could run the two outside bulbs alone, or the two outside pairs of bulbs alone. It could well be that just two bulbs, widely spaced would be plenty of light.


----------



## offpath

Hoppy said:


> From that I found that the water increases the intensity compared to an empty tank, the reflected light from the glass sides increases the intensity near those sides to at least as high as it is directly under the light, and the intensity does vary approximately with the square of the distance from the light. Also, for the configurations I was testing, the variation in intensity at the substrate level was much less than I expected.


Interesting, I'd completely forgotten about total internal reflection. I can see how that could easily make the intensity near the glass higher than at the center of the tank. I'm quite glad you mentioned that, actually, since in my modelling, the front of my tank was coming up as the least lit area, and I was looking for ways to arrange the lights to compensate for that.

Given that it's probably going to be hard to make my model much more accurate, I'd like to ask you if my proposed lighting sounds reasonable. I'm looking at having 5 T5HO bulbs (well, really 5 pairs of 3' bulbs, since it's a 6' tank) spaced evenly across the canopy. Spacing them out should give more even lighting and should help guard against taller plants shading other plants or their own lower leaves. Given the hight of the tank, canopy, and substrate, these lights will be roughly 36-38" above the substrate. Neglecting reflection, I'd used your charts to calculate ~65 micromols at the front and ~75 micromols at the center.

I'm shooting for medium light, and I'd like to try a glosso carpet. By the numbers, 5 lights, evenly spaced, sounds like it should work. Am I setting myself up for algae soup?


----------



## inkslinger

Hoppy said:


> Two pairs of T5HO would be much more light than is easily managed on a planted tank - too high, in other words. If I had your tank I would remove one of the three pairs of lights, or never turn them on. I would consider trying it with one pair near the front of the tank and the other near the back of the tank, hoping that would give reasonable uniformity in light at the substrate level, and knowing it might be too much light. If this is a single 6 bulb fixture I think I would try to rewire it so I could run the two outside bulbs alone, or the two outside pairs of bulbs alone. It could well be that just two bulbs, widely spaced would be plenty of light.



I have each pair of t5 54w stagger end to end. Until I'm ready to redesign my light's in my canopy {by removing 1 pair}
I might just run each pair 3hr's each from back to front = 9hr buy the end of the day.


----------



## Hoppy

inkslinger said:


> I have each pair of t5 54w stagger end to end. Until I'm ready to redesign my light's in my canopy {by removing 1 pair}
> I might just run each pair 3hr's each from back to front = 9hr buy the end of the day.


That should work very well. I know Tom Barr has recommended doing something like that, to make sure all plants get light, without shade.


----------



## Hoppy

offpath said:


> Interesting, I'd completely forgotten about total internal reflection. I can see how that could easily make the intensity near the glass higher than at the center of the tank. I'm quite glad you mentioned that, actually, since in my modelling, the front of my tank was coming up as the least lit area, and I was looking for ways to arrange the lights to compensate for that.
> 
> Given that it's probably going to be hard to make my model much more accurate, I'd like to ask you if my proposed lighting sounds reasonable. I'm looking at having 5 T5HO bulbs (well, really 5 pairs of 3' bulbs, since it's a 6' tank) spaced evenly across the canopy. Spacing them out should give more even lighting and should help guard against taller plants shading other plants or their own lower leaves. Given the hight of the tank, canopy, and substrate, these lights will be roughly 36-38" above the substrate. Neglecting reflection, I'd used your charts to calculate ~65 micromols at the front and ~75 micromols at the center.
> 
> I'm shooting for medium light, and I'd like to try a glosso carpet. By the numbers, 5 lights, evenly spaced, sounds like it should work. Am I setting myself up for algae soup?


I think that will work well, and it will be a very evenly lit tank, too. If you find it is too much light, you could run 2 bulbs for 3 hours, all bulbs for 2 hours, and 2 bulbs for 3 hours. That would only work if you have multiple ballasts.


----------



## forddna

Based on the chart, it appears I will have "high" light in the back of my tank. Awesome! I wanted some of the cool background plants that need high light. Now, what do you think of the front two bulbs? They are T5HO, individual reflectors, 24w. The distance from substrate to bulb is 29" though.

This is a 54g corner bowfront. Here's a pic of the canopy. Right now, the T5HOs are mounted directly to the canopy. I could space them at least 2" without worrying too much about water splashing on them. (that's a 70w in the back corner)


----------



## forddna

Also, that's a Workhorse 3 powering the 2 24w's, and that ballast is rated up to 64 (IIRC) watts. So the bulbs are overdriven a bit.


----------



## Hoppy

forddna said:


> Also, that's a Workhorse 3 powering the 2 24w's, and that ballast is rated up to 64 (IIRC) watts. So the bulbs are overdriven a bit.


I think that will work very well for the front part of the tank, but I have no idea how much light the 70 watt MH(?) light will give, nor any idea how much spread you get with that light. Very few plants have to have high light to do well, but many do need good CO2 to do well. If you have good CO2 you should be able to grow almost all plants with medium light, but they grow slower, so you aren't always pruning and worrying about building up too much plant mass in the tank.


----------



## offpath

Hoppy said:


> I think that will work well, and it will be a very evenly lit tank, too. If you find it is too much light, you could run 2 bulbs for 3 hours, all bulbs for 2 hours, and 2 bulbs for 3 hours. That would only work if you have multiple ballasts.


Yup, they'll be on multiple ballasts, so I think this configuration should be pretty easy to do. Once I have it setup, I'll see if I can't find a PAR meter to borrow, and I'll let you know how it turns out.

Thanks again for your help!


----------



## forddna

Thank you. I am working on getting CO2 going. I have a tank, regulator, and reactor. Just need a few more pieces and some help because I have never done it before.

Do you think that the T5HOs, being 29" from the substrate, will keep foreground plants low? (the ones that tend to grow taller in low light but stay low in higher light)? I'm just confused because looking at the first post here, it looks like very low par at that distance.


----------



## efface

What I am confused about is this provides no wattage of the bulbs. T8 and T5 come in several flavors. Also AHS PC and OTHER PC aren't really explained as to what they are or what wattage.

Anyone able to enlighten me?


----------



## forddna

Not sure about T8, but T5s provide the same wattage per inch. So a 24" bulb is 24w. A 36" bulb is 36w. But at any given point on the bulb, it's the same wattage coming out.

But I feel ya on the HQI deal. There's not a lot of size difference between a 70w and a 150w, so wattage should matter on those.


----------



## efface

*PAR vs Distance, T5, T12, PC*

I did not know that about t5s!

same apply for t8's?


----------



## forddna

I just learned that today. I mean, I knew they were "X inches = X watts" from shopping around, but I never got the big picture til today..lol.

Another example of something pointed out to me. I used to have 36w AH Supply kits. But they are only..what..16.5" bulbs? Now, for arguments sake, let's say 24w T5Ho is equal par to 36w PC. You are better off with the T5 because it is several inches longer and will cover a larger area. In essence, I took out 72w of PC and replaced with 48w of T5HO and I'm in better shape with the 48w.


----------



## Hoppy

Tubular bulbs, like T5, T8, and linear PC, come very close to having a wattage that is directly proportional to the length. It is close enough that I was able to determine that all PC bulbs give the same PAR at a given distance from the bulb, all T5HO's give the same PAR at a given distance, and from that it is obvious that all T8's, normally driven, do the same. The disadvantage of the lower wattage bulbs is that they only light up a shorter section of big tanks, since they don't extend the full length of the tank. Likewise, a long, high wattage bulb over a short tank doesn't give more light for that tank, since much of the bulb isn't over the tank.

Screw-in CFL bulbs are different, because they all have virtually the same dimensions, with higher wattage bulbs just having more turns of slightly larger radius than lower wattage bulbs. There, you do have to consider wattage in figuring how much light you will get from a bulb.

MH bulbs, obviously are similar to the CFL bulbs, so I would expect that wattage would have to be considered for them too. The line on that chart for MH bulbs is from one person's MH bulb of one wattage - the line is there only to give a general idea about how much brighter they are. I don't have nearly enough data to predict what any MH bulb or fixture will do.

LED's are also dfferent, with at least two different wattage classes of LEDs available that can light up a tank, and each of them can be operated over a range of currents (wattages).


----------



## crf529

Hey Hoppy,

Looking at the AHS PC light intensity, would you expect similar performance for the ANS Illummax series of fittings with their aluminium reflector?

http://freshnmarine.com.sg/estore/product_info.php?products_id=774


----------



## forddna

Hoppy, I will try to borrow a PAR meter and post results. I can see the MH shimmering effect near the front of the tank, so that HQI is spreading a lit of light, I believe.


----------



## Hoppy

crf529 said:


> Hey Hoppy,
> 
> Looking at the AHS PC light intensity, would you expect similar performance for the ANS Illummax series of fittings with their aluminium reflector?
> 
> http://freshnmarine.com.sg/estore/product_info.php?products_id=774


No, I wouldn't expect that fixture to have as good a reflector as the AH Supply reflectors, because they aren't as wide, nor as deep. To collect and redirect all of the light, the reflector has to be considerably wider than the bulb, to give room at the sides for the light to get around the bulb, and it should have the bulb down in the reflector, so the reflector sides stick up at least to the height of the bulb. It doesn't look like that one does that, but the AH Supply one does. This fixture might give 1/5 to 1/3 less PAR than the AHS light. Without actually measuring its output I can only guess.


----------



## crf529

Ah k, cheers for that Hoppy!


----------



## jarickc

*Thank you*

Hoppy, 
I spent the better part of the day trying to figure out a cheep way to increase the light on my tank. Reading the forums about 4WPG and Rex's page on lumen/in^2 had me thinking I had a low light tank at 2 WPG and maybe 15 Lm/in^2 but your posts if i am reading them right say that my 2x39 watt T5HO on top of my 18" tall tank is actually high if not slightly too high.
You not only saved me time and money, but also shed the light of science on things: I like data and charts I hate anecdotes.
If i have misinterpreted things let me know otherwise I am going to assume that my lights will not be the downfall of my HC or Red Nesaea, for that we will assume i messed up ferts or CO2.

TL;DR Hoppy, you're a god I love you.


----------



## Hoppy

jarickc said:


> Hoppy,
> I spent the better part of the day trying to figure out a cheep way to increase the light on my tank. Reading the forums about 4WPG and Rex's page on lumen/in^2 had me thinking I had a low light tank at 2 WPG and maybe 15 Lm/in^2 but your posts if i am reading them right say that my 2x39 watt T5HO on top of my 18" tall tank is actually high if not slightly too high.
> You not only saved me time and money, but also shed the light of science on things: I like data and charts I hate anecdotes.
> If i have misinterpreted things let me know otherwise I am going to assume that my lights will not be the downfall of my HC or Red Nesaea, for that we will assume i messed up ferts or CO2.
> 
> TL;DR Hoppy, you're a god I love you.


You are reading the chart correctly. And, just leave $$$ on the collection plate :hihi:


----------



## Seattle_Aquarist

Hi Hoppy,

I always believe quantitative data is better than "rules of thumb", thank you for providing helpful data. I do have a question however, where did your ranges for Low, Medium, and High light come from?

I was trying to research PAR vs "Low, Medium, and High" light levels and I came across this thread at TBR which seems to use higher levels of PAR for the ranges. 

Hopefully we will eventually reach a point in this hobby were we have standardized PAR values for relative terms like "Low, Medium, High" light. Then we can properly classify what specific plant species require in PAR / light levels.


----------



## Hoppy

I got those light ranges from Tom Barr, but several months after that thread you referenced. I think we were all struggling to figure out what PAR values meant at that time. And, I believe it was later that Tom measured the ADA tanks at Aquaforest in SF and found just how low the light levels in typical Amano tanks were. He also began reducing his own light levels quite a bit after that, so I assume it was that experience that led to the ranges he suggested.

I suspect there is a lot more to learn about appropriate PAR values.

Another thing to keep in mind is that the chart is about PAR levels at the substrate, not up higher in the tank. Since the light intensity goes up inversely proportional to the square of the distance from the light, the intensity higher in the tank is always much higher than at the substrate. But, you can only specify intensity at one distance - at other distances it is just a matter of geometry.


----------



## tom855

Not to make what will certainly sound like a corny joke, but this thread is truly one of the most "enlightening" things I have ever encountered on the board. I've been fooling around for almost ten years with a variety of planted tanks, lights, CO2, ferts, and the like, and was never able to find a tank configuration that would provide stable, consistent growth. I suspect that many of the issues I've faced over the years would have been solved if I had only known and understood what's in this thread.

Thanks Hoppy, for the fantastic empirical data. I never would have suspected some of the conclusions. I for one have been using way too much light for a longgg time. Getting the lighting to a reasonable level will now allow me to focus on other issues...... for the next ten years. LOL.

Thanks Hoppy! This is an awesome thread!!!!!

Tom 


.


----------



## Seattle_Aquarist

Hi Hoppy,

Thank you for clarifying where the range information came from. I could not find when reading your post if the PAR readings were taken in "free air" or underwater in an aquarium where internal light reflection off of the sides might effect the readings.

BTW, Inverse Squared Rule(s)! LOL!


----------



## Hoppy

Seattle_Aquarist said:


> Hi Hoppy,
> 
> Thank you for clarifying where the range information came from. I could not find when reading your post if the PAR readings were taken in "free air" or underwater in an aquarium where internal light reflection off of the sides might effect the readings.
> 
> BTW, Inverse Squared Rule(s)! LOL!


Most of the readings were in tanks of water, but some were in air. As long as the readings are only in the middle of the tank, the reflections off the glass aren't in the picture. But, I have seen that the intensity in the middle is a little higher with water than without water, something I suspected, because the water "focuses" the light a little bit. I have ignored that effect, since it isn't big.


----------



## dutchy

Hi Hoppy,

Are you sure the PAR graph on T5HO's is correct? I will clarify my question.

I measured PAR on my tank. The tank is 72 x 24 x 24. the distance lights / substrate is around 20 inch. I have 4 rows of T5HO daylight bulbs with reflectors.

Your graph says that 1 T5HO gives me 65 micromols at that distance. Also the graph says: For 2 to 4 bulbs, multiply PAR by number of bulbs.

That would mean, according to that statement, 65 x 4 = 260 micromols. The result of the PAR measurement with water: 95 micromols.

That's a considerable difference. Also this could lead to people not using enough light.

Correct me if I'm wrong.

regards,
dutchy


----------



## Hoppy

dutchy said:


> Hi Hoppy,
> 
> Are you sure the PAR graph on T5HO's is correct? I will clarify my question.
> 
> I measured PAR on my tank. The tank is 72 x 24 x 24. the distance lights / substrate is around 20 inch. I have 4 rows of T5HO daylight bulbs with reflectors.
> 
> Your graph says that 1 T5HO gives me 65 micromols at that distance. Also the graph says: For 2 to 4 bulbs, multiply PAR by number of bulbs.
> 
> That would mean, according to that statement, 65 x 4 = 260 micromols. The result of the PAR measurement with water: 95 micromols.
> 
> That's a considerable difference. Also this could lead to people not using enough light.
> 
> Correct me if I'm wrong.
> 
> regards,
> dutchy


That really is a big difference, and one I can't explain. The T5HO numbers I used come from many different fixtures, taken by several people, so I trust it to be reasonably accurate. I did measure PAR in one tank owned by a member of our local aquatic plant group, with 2 and 4 bulbs being used in a Catalina fixture. The 2 bulb numbers matched the chart pretty well, but not the 4 bulb. The reason I attributed that to was that the fixture had an inoperative MH light in the middle, causing several inches of separation between the pairs of bulbs. And, the measurements were at distances not carefully measured, in a tank that had enough plants to partially shade the sensor. All of those factors led me to believe that my chart was likely to be accurate.

In measuring PAR, you have to be very careful not to shade the sensor with your arm, with plants, with the cable to the sensor, etc. A bit of shading that you can't even see by eye can drop the reading in half.

One way to check your readings is to measure PAR at a closer distance, above where any shading occurs, measure at 2 or 3 distances, then plot the readings on log-log paper to confirm that you have an inverse square drop off of intensity. If you don't, there are errors in the readings. If you do, you can extrapolate to the substrate distance to find the PAR at that location.


----------



## plantbrain

This is one reason it's very hard to generalize with PAR or light in general without actually measuring the tank with a light meter.

In otherwords,it's still a guess.

Now if you have the exact same set up, or enough general experience, then you might be able to hit a reasonable target.

You can say something if the light systems, distances, etc are exactly the same. But then it's harder to generalize.

That is the trade off, if you tried to apply this to dosing without measuring anything....you can quickly see you are guessing a lot. You can still eyeball it, but .......that does little good for quantifying or getting a good range etc.

I suggest and still suggest a light meter if you are serious.
Rent, group buy etc........

Then you know.

Why expect others to make some chart and table for you that is better than say the watt/gal rule? No chart is going to save folks here. I think that is what many are thinking and wanting.

I do not think that is realistic.

Nutrients are the easiest thing we can measure, light is the next, CO2 is by far the hardest. All this talk about "each aquarium being unique and it's own ecosystem" blah blah seems tossed out the window when it comes to light and CO2.

You have 3 main things(light/CO2/nutrients),* if you apply a standard to one of them, then it should apply fairly to all 3.* 

Regards, 
Tom Barr


----------



## dutchy

Hoppy said:


> In measuring PAR, you have to be very careful not to shade the sensor with your arm, with plants, with the cable to the sensor, etc. A bit of shading that you can't even see by eye can drop the reading in half.
> 
> One way to check your readings is to measure PAR at a closer distance, above where any shading occurs, measure at 2 or 3 distances, then plot the readings on log-log paper to confirm that you have an inverse square drop off of intensity. If you don't, there are errors in the readings. If you do, you can extrapolate to the substrate distance to find the PAR at that location.


I don't measure with my arm, the sensor is on a thin stick with the sensor mounted at the end with a 45 degree angle. The stick also supports the cable. I measure from the side of the tank inwards and turn the sensor slightly to get the best readings.

I measured various tanks. One had two T5's and reflectors which gave 50 micromols at the substrate at a depth of 18 inch.

I also measured a difference of 30% within various brands of bulbs with the same Kelvin number.

Mounting good reflectors gave a 50% increase.

To compare I took another reading, with a 6500K T5HO and reflector at 20 inch in open air. Your reading is around 60 micromol, mine around 40.

Going back to what I said before that I measured up to 30% differences, this seems to be correct.

This means that any sort of graph is unusable, and the only thing left is like Tom says, buy one.

Another issue is that with multiple bulb setups, reflectors will shade a lot of light spreading around, so light of bulb number 1 might actually hardly reach below bulb number 4. What I measure in my tank supports this. If I only use the two bulbs in the back, I only get 20 micromols in the front.
Also the diagonal distance will be longer which also makes PAR fall off more.

So the statement in the graph to multiply the reading by the number of bulbs can't be correct IMO.

On the other hand, I measured a tank with four T8's with a white painted canopy at a distance of 15 inch. This one measured 60 micromols, which is close to your readings and the "multiply by four" statement. But here, the light could spread around because there were no reflectors. This confrims what I said about reflector shading. 

I got triggered by this because someone on the BarrReport thought he had medium light with a two bulb fixture (one plant grow purple type) with a 30 inch deep tank. This got me wondering and I started to look at your graph, which took me here.

I hope it helps, maybe it doesn't 

regards,
dutchy


----------



## Hoppy

dutchy said:


> I don't measure with my arm, the sensor is on a thin stick with the sensor mounted at the end with a 45 degree angle. The stick also supports the cable. I measure from the side of the tank inwards and turn the sensor slightly to get the best readings.
> 
> I measured various tanks. One had two T5's and reflectors which gave 50 micromols at the substrate at a depth of 18 inch.
> 
> I also measured a difference of 30% within various brands of bulbs with the same Kelvin number.
> 
> Mounting good reflectors gave a 50% increase.
> 
> To compare I took another reading, with a 6500K T5HO and reflector at 20 inch in open air. Your reading is around 60 micromol, mine around 40.
> 
> Going back to what I said before that I measured up to 30% differences, this seems to be correct.
> 
> This means that any sort of graph is unusable, and the only thing left is like Tom says, buy one.
> 
> Another issue is that with multiple bulb setups, reflectors will shade a lot of light spreading around, so light of bulb number 1 might actually hardly reach below bulb number 4. What I measure in my tank supports this. If I only use the two bulbs in the back, I only get 20 micromols in the front.
> Also the diagonal distance will be longer which also makes PAR fall off more.
> 
> So the statement in the graph to multiply the reading by the number of bulbs can't be correct IMO.
> 
> On the other hand, I measured a tank with four T8's with a white painted canopy at a distance of 15 inch. This one measured 60 micromols, which is close to your readings and the "multiply by four" statement. But here, the light could spread around because there were no reflectors. This confrims what I said about reflector shading.
> 
> I got triggered by this because someone on the BarrReport thought he had medium light with a two bulb fixture (one plant grow purple type) with a 30 inch deep tank. This got me wondering and I started to look at your graph, which took me here.
> 
> I hope it helps, maybe it doesn't
> 
> regards,
> dutchy


Thanks, that is very interesting. For sure, you have to actually measure how much light you have to know it with any accuracy. Unfortunately, first you have to buy the light, so you need some kind of guide to determine which light to buy. That is the only purpose of the chart.

I have some data from a variety of multiple bulb T5HO fixtures, and those come very close to giving 4 X the light from one bulb when 4 are used, or 2X the light from on bulb when 2 are used. Beyond 4 bulbs, I feel quite sure you can't just add up the light outputs. And, if the 4 bulbs are widely separated I also know that you won't get 4 x what one bulb gives. But, few economical light fixtures separate the bulbs any further than necessary to fit them in.

Eventually I hope we will accumulate enough data to make a chart of this nature even more useful.


----------



## forddna

dutchy, your tank is 24" high, and your distance from light to substrate is 20"? Do you have 4" of substrate and the light mounted right at the surface or something?? (slight sarcasm, yes, but good natured)


----------



## chrisnif

Hoppy,

First of all thank you so very much for the chart, it is completely awesome...

I've been going back and forth on lighting for my 90 gallon. I want low light, but I'd like halide (HQI) for the "shimmer" and having an open top so that some of the plants can flower above the water.










This is the light I built for my 20 high (reef) tank. It has a 70W electronic ballast running a ushio bulb, I built it so I could adjust the height and articulation a bit (mainly to keep algae off the front glass). At this point it's maybe 6 inches from the water, tank is 16 tall, so 22 inches from the substrate, which is probably WAY high light (and I plan on upgrading to 150W, so I'll have the 70W lying around). The main part of the fixture is a 300w halogen fixture that was gutted (the bulb connector is the same).

Anyway, I digress. On of my plans for the 90 would be to put two of these on the 90 and try to figure out the height above the substrate that would be required. I can raise it as high as needed, but that is where I'd like the input from the expert(s). The 90 is 24", probably 3 inches of substrate, so if I place the light 12" above the water, so about 33 inches from the substrate. Is that high enough, or would I need to go higher? Also, I have the option of removing the reflector if that would help me not have to have the light like 36" above the water. 

Again it will be adjustable, so if I get a crazy outbreak of algae I could adjust, but I don't plan on starting with CO2 (maybe later, but not from the get go).

Thanks again, one day I'll stop thinking and just do it


----------



## Hoppy

I can't help with MH fixtures. That is a project someone else will have to take up.


----------



## chrisnif

I admire a person who admits when they just don't know everything about everything... I find this hard to do at times roud:

Other than the obvious algae, PAR meter (I am thinking about renting from my local reef club but the thing is hard to actually get), is there a tell tale "wow that's too much light" ?


----------



## dutchy

forddna said:


> dutchy, your tank is 24" high, and your distance from light to substrate is 20"? Do you have 4" of substrate and the light mounted right at the surface or something?? (slight sarcasm, yes, but good natured)


The tank is 24 inch high, there's 2 inch of substrate at the front to middle and the lights are 2 inch from the water surface. At the back there's 4 to 5 inch of substrate.

regards,
dutchy


----------



## plantbrain

dutchy said:


> The tank is 24 inch high, there's 2 inch of substrate at the front to middle and the lights are 2 inch from the water surface. At the back there's 4 to 5 inch of substrate.
> 
> regards,
> dutchy


Hummm..........might try and see if the light could be raised about 6-8" above the water's surface.

This seems initially counter intuitive.
But this reduction in intensity is offset by a better, more even spread and less hot spotting.

You have enough light to burn, and can adjust the intensity unlike many in the USA. I'm not sure if the hood you have will allow you to raise the light though.

Regards, 
Tom Barr


----------



## dutchy

Hi Tom,

No need to raise the lights. I'm not using 95 micromols, but 55 micromols without reflectors but with a white painted hood, and light can spread around that way.

if I need less, I just turn the knob 

regards,
dutchy


----------



## Hoppy

chrisnif said:


> I admire a person who admits when they just don't know everything about everything... I find this hard to do at times roud:
> 
> Other than the obvious algae, PAR meter (I am thinking about renting from my local reef club but the thing is hard to actually get), is there a tell tale "wow that's too much light" ?


Yes, when you start admiring the beauty of a big field of black brush algae, you know you have too much light.


----------



## RipariumGuy

Hey Hoppy, I have a question concerning PAR... What does it stand for? And what is it?


----------



## RipariumGuy

Oh yeah, this has *my vote for an artical or sticky!*


----------



## Hoppy

JakeJ said:


> Hey Hoppy, I have a question concerning PAR... What does it stand for? And what is it?


Photosynthetically Active Radiation, the amount of photons of light in the spectrum that plants respond to, passing through an area - micromols per square meter per second.


----------



## AdrienDeLaChicago

Hoppy said:


> To my surprise, the mylar was the least effective.....


I am very glad you covered this. I found this product on my own by doing a Google search and thought this would be the best option to create my own reflectors. Glad to know beforehand that it is not effective. I will stick with an ultra-white high gloss paint.


----------



## DANIELSON

Question- I found a great deal on a power compact fixture it's a single 24" 65w bulb with as far as I can tell a good reflector. It will be placed on top of my tank with 17" distance from substrate to light. Directly under this lighting would that be med lighting? This will be in the front of a 35g corner tank.


----------



## efface

*PAR vs Distance, T5, T12, PC*

danielson did you not look at the chart on the first page?

reference the number of inches vs "PC" power compact


----------



## DANIELSON

Sorry i guess what i was asking was if the Watt of the bulb plays a difference? I saw the chart and thought that there has to be a differance between a 10W and a 96W bulb. So it being a 65W bulb if that would still be the med light or not is all im asking.


----------



## plantbrain

dutchy said:


> Hi Tom,
> 
> No need to raise the lights. I'm not using 95 micromols, but 55 micromols without reflectors but with a white painted hood, and light can spread around that way.
> 
> if I need less, I just turn the knob
> 
> regards,
> dutchy


I know, that's why I suggested raising it to see the difference in the effect vs changing the intensity, the effect is/should be different.
You might find this more useful than turning the knob.

Regards, 
Tom Barr


----------



## Hoppy

PC bulb wattage is a measure of the length of the bulb, more than anything else. Yes, the longer bulbs produce more light in total, but not significantly brighter light directly under the bulb. The real problem with guessing how much light a PC fixture will give you is that they have been made with everything from essentially no reflector, to super reflectors, as used in AH Supply kits. That makes at least a 2 to 1 variation in PAR. If this one has a reflector much like the AH Supply ones, it should give you medium light, but it is more likely to give you low medium or low light. (Do you have a picture of the light, showing the reflector?)


----------



## DANIELSON

I dont have a pic currently ill try to get one. It is a coralife fixture if that helps any. Not sure if they are consistant on reflectors.


----------



## Aquaticz

I am slighly confused... I have two tanks - A 55 gallon and an 80 gallon.
Both have DIY fixtures using A&H CF fixtures - 4 X 55 watt 
On the 55 the fixture lays on top of the tank 16 inches above the substrate 
On the 80 the fixture lays on top of the tank 21 inches above the substrate.
Would both tanks be considered high light? 

Would a piece of 1/4 inch glass between the bulbs and the top of the water make a difference? 

I've also a 40 gallon with a single T-8 - 25 watt - 50/50 that is 14 inches above substrate. Does this tank even qualify as low light? 

Thank you for all your help & wisdom


----------



## Bunbuku

Very interesting thread! I just bought a water proof Lux meter with a gift card
http://www.aquacave.com/mw700-lux-light-meter-brw-waterproof-probebr-by-milwaukee-instruments-2954.html. 

Playing around with it I get the following readings:
1) Outside, midday full sun - 105,000
2) About 11'' from my AM 150 watt MH fixture (ADA 8000K bulb) - 23,000
3) Underwater at substrate level in my ADA-60P - 6,800 (fixture 11" from water surface)
4) My office with west facing blinds open at midday (lights off) - 146

I guess that means my tank fits the definition of "high" light. Is there a approx. conversion from Lux to PAR?


----------



## Hoppy

Aquaticz said:


> I am slighly confused... I have two tanks - A 55 gallon and an 80 gallon.
> Both have DIY fixtures using A&H CF fixtures - 4 X 55 watt
> On the 55 the fixture lays on top of the tank 16 inches above the substrate
> On the 80 the fixture lays on top of the tank 21 inches above the substrate.
> Would both tanks be considered high light?
> 
> Would a piece of 1/4 inch glass between the bulbs and the top of the water make a difference?
> 
> I've also a 40 gallon with a single T-8 - 25 watt - 50/50 that is 14 inches above substrate. Does this tank even qualify as low light?
> 
> Thank you for all your help & wisdom


Both the 55 and the 80 probably have high light, but the 55 probably has excessively high light or very close to it. If the 80 gallon tank is more than 16 inches or so in front to back depth, you may have only high medium light unless the lights are pretty close together (two rows of 2 bulbs) and that would result in a drop off in intensity near the front and back. Clean glass doesn't reduce the intensity much at all. 

I doubt that the 40 gallon tank has enough light for anything except mosses, and being a 50/50 bulb (half actinic) it would likely be even less effective.


----------



## Hoppy

Bunbuku said:


> Very interesting thread! I just bought a water proof Lux meter with a gift card
> http://www.aquacave.com/mw700-lux-light-meter-brw-waterproof-probebr-by-milwaukee-instruments-2954.html.
> 
> Playing around with it I get the following readings:
> 1) Outside, midday full sun - 105,000
> 2) About 11'' from my AM 150 watt MH fixture (ADA 8000K bulb) - 23,000
> 3) Underwater at substrate level in my ADA-60P - 6,800 (fixture 11" from water surface)
> 4) My office with west facing blinds open at midday (lights off) - 146
> 
> I guess that means my tank fits the definition of "high" light. Is there a approx. conversion from Lux to PAR?


Since Lux meters weight their readings to match human eye light sensitivity and PAR meters weight their readings to match what plants "see", there isn't any conversion factor between Lux and PAR. For one specific bulb you could calibrate the Lux meter with a PAR meter and use it to adjust the light intensity for that specific bulb, or monitor the loss of intensity over time. But, you couldn't use it to measure PAR with a different bulb.


----------



## ltsai

Does the chart has a relationship with pearling of the plants?

I have a 2x1x1 ft tank and with 2x24W T5H0 on the top of the tank on its stand. According to the chart, a single T5HO bulb gives high lightning. With both bulbs turned on, I can achieve pearling from the plants, especially java ferns. 

This is a dual bulb fixture with a shared reflector.


----------



## reybie

ltsai said:


> Does the chart has a relationship with pearling of the plants?
> 
> I have a 2x1x1 ft tank and with 2x24W T5H0 on the top of the tank on its stand. According to the chart, a single T5HO bulb gives high lightning. With both bulbs turned on, I can achieve pearling from the plants, especially java ferns.
> 
> This is a dual bulb fixture with a shared reflector.


I have a similar experience, if I use one bank of the T5 HOs, no pearling, 2 banks result in pearling.


----------



## Hoppy

ltsai said:


> Does the chart has a relationship with pearling of the plants?
> 
> I have a 2x1x1 ft tank and with 2x24W T5H0 on the top of the tank on its stand. According to the chart, a single T5HO bulb gives high lightning. With both bulbs turned on, I can achieve pearling from the plants, especially java ferns.
> 
> This is a dual bulb fixture with a shared reflector.





reybie said:


> I have a similar experience, if I use one bank of the T5 HOs, no pearling, 2 banks result in pearling.


Pearling happens when the plants are growing fast, producing O2 fast enough that it can't dissolve in the water that quickly, so it forms bubbles of O2. That takes light, CO2 and other nutrients. If you have even a single T5HO bulb in a T5HO fixture (T5HO ballast), located 12 inches from the substrate, even with a poor reflector, you should get pearling if you also have good CO2 and non-limiting fertilizing.


----------



## nemosreef

I have a coralife 2x96watt PC fixture. I am only using one light which would be 96watts. What would my lighting be considered? It is 20" from the substrate. 38gal. Tank.


----------



## antbug

Wow, what a great thread. Thanks for all the info Hoppy. I'll have to borrow that meter when Jose is done and send you my data for the T6 I have.


----------



## Dave-H

If I could get my hands on one I'd love to measure the PAR levels in my tank. Lots of interest in corner tank lighting strategies, it turns out!


----------



## Sharkfood

I refer to the chart on this thread all the time. Can this become a sticky yet?


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## forddna

NEEDS to be a sticky!!!!! I come back to it all the time, too!!


----------



## HouseofZoo

Wow, I just found this thread. According to the chart I'm at the medium to high light with just my one fixture. 

I guess I need to raise the one up and remove the other one altogether.

Definitely worth a sticky!!


----------



## garuf

An exceptional post, thanks Hoppy.


----------



## forddna

HouseofZoo said:


> Wow, I just found this thread. According to the chart I'm at the medium to high light with just my one fixture.
> 
> I guess I need to raise the one up and remove the other one altogether.
> 
> Definitely worth a sticky!!


 
That's another issue/question. What PAR difference is there between 2-4 individual reflector T5HOs, and a 2-4 bulb fixture without individual reflectors?


----------



## Hoppy

forddna said:


> That's another issue/question. What PAR difference is there between 2-4 individual reflector T5HOs, and a 2-4 bulb fixture without individual reflectors?


The data I used came from both clip on single bulb reflector lights, and shaped single reflector for multiple bulbs lights. I couldn't see any significant differences in the PAR outputs. But, I'm sure there are differences. The charts only get you close to the desired PAR. You have to use a PAR meter to get an accurate measurement for your tank, fixture and installation. I'm not convinced that is necessary, but it might be desirable.


----------



## jcardona1

*Results of my PAR testing*

Hey folks, 

Just wanted to share the details of some recent PAR testing I did. I borrowed a PAR meter from my local club (Hoppy and Tom). I wanted to compare this to the light fixtures I had to see how reliable the information is, because we all know every fixture and light bulb is different. I think you'll see that PAR charts are meant to only be used as a rough guide. The only real way of knowing how much light you have is to test YOUR specific setup. There are way too many real world variables that will affect readings from one tank to the other. 

Here's some important things you should know about my testing: 
1. The Lowes and Current/Nova fixtures were tested on a standard 20g tank, with water. The sensor was placed in the middle of the tank, right under the fixture. 

2. The Lowes & Current/Nova lights are 48" long, and the tank is only 24" long. To avoid having any stray light afftect the reading, I wrapped the overlapping section of the fixture with a towel. Removing the towels caused an increase of 4-5 micromols. 

3. The Lowes fixture is black metal, even where the bulbs are. This is obviously isn't a good color for reflection, so I also wrapped the inside with aluminum foil and took more readings. 

4. The Current/Nova fixture uses two bulbs, very close together. This has a very cheap thin aluminum reflector that goes over both bulbs. 

5. The bulbs in the Lowes & Current/Nova fixture are fairly old, all over a year. Please keep this in mind as new bulbs may give a higher reading. The only bulbs that were brand new were the Giesemann bulbs in my Catalina fixture (3 days old at the time of testing). 

6. I only took one reading with the Catalina fixture since it's mounted to a hanging bracket and the tank is heavily planted. I may try some more readings, but for the time being, it's just at 28". Also note that this is a 4-bulb fixture. I only tested 2 bulbs, in the outer most banks. 

7. For the Current/Nova fixture, I had 3 types of bulbs. I took individual readings from each bulb and compared the results as seen below. Again, keep in mind that bulb age may be a factor. I did not go out and buy new bulbs to test this fixture. 
​Any questions please feel free to ask! I have a few more desktop lamps/fixtures that I will be testing in the days to come


----------



## Dave-H

I'm about to order a 2 x T5HO fixture from Catalina and mount it about 28 inches off the substrate. Per hoppy's chart, this would put me in medium light but your findings show the PAR a bit lower.

Very interesting. What makes this tough is that even if you owned a PAR meter you'd have to buy and test the fixtures before you knew which one was best!


----------



## jcardona1

Dave-H said:


> I'm about to order a 2 x T5HO fixture from Catalina and mount it about 28 inches off the substrate. Per hoppy's chart, this would put me in medium light but your findings show the PAR a bit lower.
> 
> Very interesting. What makes this tough is that even if you owned a PAR meter you'd have to buy and test the fixtures before you knew which one was best!


Yeah exactly. I'm strongly considering purchasing one to have on hand at all times. But it's not an easy expense to justify for a meter that won't get used too often. I'm lucky I was able to borrow one from Tom  

Individual testing is really the only way to know. It would be like trying to guess what our co2 levels are without the use of a drop checker, based on the BPS rate from other tanks. As we know, it would be ridiculous to even try and make this comparison. I feel the same goes for lighting, to a certain extent.


----------



## Dave-H

Yea, but then again the stakes are different. If you are guessing at CO2 you can easily gas your fish. If you are guessing at light you will have a decent idea of what's going on after a while.

I'm gonna put my lights up, give it a month and see how things are looking. Mainly I just want to measure more things and get analytical.


----------



## Hoppy

Jose, are you sure the Current/Nova fixture is T5HO and not T5NO? Your results look a lot more like NO results than HO.

The effect of putting aluminum foil in the T8 fixture is about what I would expect - it doesn't take a sophisticated reflector to double the light you get compared to no reflector at all.

In general your results, except for the Current/Nova data, look consistent with mine. There is scatter in the data, for sure. But, the charts do allow you to get in the right ballpark with lighting, something I don't know any other way to do.


----------



## jcardona1

Hoppy said:


> Jose, are you sure the Current/Nova fixture is T5HO and not T5NO? Your results look a lot more like NO results than HO.
> 
> The effect of putting aluminum foil in the T8 fixture is about what I would expect - it doesn't take a sophisticated reflector to double the light you get compared to no reflector at all.
> 
> In general your results, except for the Current/Nova data, look consistent with mine. There is scatter in the data, for sure. But, the charts do allow you to get in the right ballpark with lighting, something I don't know any other way to do.


Yeah, I'm positive. The bulbs were PowerGlo and LifeGlo T5HO. I think the issue may be the age of the bulbs. But as I mentioned, I didn't have any new bulbs to try out. Not to mention the overall design and reflectors of the Current fixture is very low quality when compared to the Catalina fixture.


----------



## Hoppy

Is this the fixture: http://www.current-usa.com/novaextremet5hox2.html If so, that could explain the low PAR, since that appears to use reflectors that are barely wider than the bulb, leaving little room for light to get from the back of the bulb to the front. I have read that the really good reflectors increase the light output by more than 2.5 times, and these clearly aren't that good.


----------



## jcardona1

Hoppy said:


> Is this the fixture: http://www.current-usa.com/novaextremet5hox2.html If so, that could explain the low PAR, since that appears to use reflectors that are barely wider than the bulb, leaving little room for light to get from the back of the bulb to the front. I have read that the really good reflectors increase the light output by more than 2.5 times, and these clearly aren't that good.


Yeah, looks very similar, although mine didn't come with the legs. And yes, the bulbs are VERY close together. In fact, it's difficult to remove the bulbs at times because space is so tight. And the reflector is horrible. I would not recommend this fixture to anybody.


----------



## antbug

Jose ~ Please let me know when you are done with the meter. I would like to test my tanks. I can wait till the next meeting, 11/2, if you are going.

Thanks ~ Anthony


----------



## jcardona1

antbug said:


> Jose ~ Please let me know when you are done with the meter. I would like to test my tanks. I can wait till the next meeting, 11/2, if you are going.
> 
> Thanks ~ Anthony


Sure, I'll let you know. Should be in the next few days.


----------



## RipariumGuy

Heya lighting gurus, I have a question. How much light would a fixture with a rounded, painted white metal desk lamp with a 13w CF bulb over a 2.5g tank give me?


----------



## Hoppy

JakeJ said:


> Heya lighting gurus, I have a question. How much light would a fixture with a rounded, painted white metal desk lamp with a 13w CF bulb over a 2.5g tank give me?


Go to the other sticky in this forum, but that desk lamp doesn't have a real reflector, I think. It is intended for reflector bulbs, I think. If that is so, the charts in that sticky won't be accurate.


----------



## Buc_Nasty

Great thread Hoppy

I previously had two 24 inch coralife power compact double lights (2x65 watt) with 6700K bulbs at each end of my 125 gallon. I upgraded to 2 nova extreme 24 inch (2x24 watt) T5HO with individual reflectors. 

The power compacts seem far brighter to the eye...they light up the whole tank and the whole room a lot more, especially reflecting off my bright white sand. Its hard to believe the PAR for the T5HO is so much higher and I'd NEVER believe it if I didnt see your data. 

The T5HO with a 6700K and a 10,000K bulb do bring out the colors of the fish and the plants more, and are still sufficiently bright. I honestly think the T5HO look better than the PC, completely ignoring everything else like PAR and costs.

For everyone debating switching to T5HO... 
I calculated my costs...This is for my 125g tank with a 24 inch fixture on either end and no light over the middle 1/3 of the tank. PC is what I said above......the 24 inch coralife 2x65 watt fixture with bulbs, T5HO is my new 24 inch Nova Extreme 2x24 watt with bulbs

PC
Initial Cost ...............................................$300
Electricity/year (@ 11 hrs per day in MA).......$104
Replacement Bulbs (debatable).....................$100 (4x$25) per 6-12 months 

T5HO
Initial Cost................................................$120
Electricity/year (@ 11 hrs per day in MA).......$42 
Replacement Bulbs (debatable).....................$60 (4x$15) per 18-24 months


Cost per year after initial purchase T5HO = $72, PC = $204

Other factors
- Nova T5HO comes with mounting legs, which for the PC are hard to find and an extra $30 (better off building your own. 

- PC are much louder because of the fans, which also take more power (not included in computation). T5HO dont need fans because they don't give off NEARLY as much heat.

- PC cant be rested directly on top of the glass aquarium lids or the extreme temperature and condensation cracks the lids! And you need to use lids b/c the extreme heat causes so much evaporation and condensation the lights would get soaked and it says all over the box you MUST put them on top of lids or they'll get water damage.

(one of my T5HO will be paid off in a year via electricity savings compared to PC. Lets just hope i can sell the PC on craigslist)

On top of the far higher PAR values of T5HO...how could anyone choose PC??!!


----------



## jerry1

From a total newbie perspective, great thread and thanks for the testing!

Looks like I have a great starting point. I have 72 gallon bowfront with a 3x54W Catalina fixture w/ 2 switches. I bought if because of the versatility and I really didn't know what I would need. Right now, I'm using a 10000K and 6700K and their standoff legs. I use the 3rd bulb only when I want to turn the lights on during times when the timer is not typically on. I am putting together my Co2 system now so I'm using excel 1x every 2 days. 

My data is: 
23" tall tank
With 3" standoff legs, lights are 23.5" off the gravel

Some plants are doing better than others but I suspect that once I get the Co2 online, things will improve.

Question, how do people raise their light fixtures more off the tank? I can't suspend it from the ceiling and other than the legs I bought from Catalina, I'm not sure what I would use.

Thanks


----------



## fjf888

*my exact fixture.*



Hoppy said:


> Is this the fixture: http://www.current-usa.com/novaextremet5hox2.html If so, that could explain the low PAR, since that appears to use reflectors that are barely wider than the bulb, leaving little room for light to get from the back of the bulb to the front. I have read that the really good reflectors increase the light output by more than 2.5 times, and these clearly aren't that good.


This may explain the slow growth I am having. I have been using 2x54 instead of 4x54, based on recommendations I have received from Tom and confirmed using this graph, with CO2 to the point of making the fish very uncomfortable. So if these reflectors are truly crap then I might actually need to use 3-4 bulbs, to get decent lighting in my 24 in deep tank. My bulbs are also a year old, so that could be a factor as well.

Thanks for providing this highly useful info.

Fred


----------



## tom855

I have that exact fixture over my 58G, with about 20" from the glass to the substrate. I was always fighting BBA with it on the glass. After reading thread I realized it was way too much light. I put it up on 3" legs and am still growing the stuff like mad on the taller plants. My personal opinion is that it pumps out a lot of light, but that's not a fact. I may actually invest in a PAR meter just to see what the numbers really are. Yes, the bulbs are close together, but it sure pumps out the light.

Tom 

.


----------



## kevmo911

I have a Coralife 96w PC Quad fixture over my tank. Since (according to the 2nd chart) a 2-bulb PC seems to have similar lighting to a single T5NO tube, can i assume that a 4-bulb PC fixture is roughly equivalent to 2 T5NO's?


----------



## Hoppy

PC bulb fixtures are hard to judge. Some have virtually no reflectors, others have very good reflectors. Since over half of the light comes by way of the reflector that makes a big difference in how much light they produce. I don't know how good the reflector is in that light - do you have a picture of it?


----------



## Buc_Nasty

> Originally Posted by Hoppy
> Is this the fixture: http://www.current-usa.com/novaextremet5hox2.html If so, that could explain the low PAR, since that appears to use reflectors that are barely wider than the bulb, leaving little room for light to get from the back of the bulb to the front. I have read that the really good reflectors increase the light output by more than 2.5 times, and these clearly aren't that good.


If those fixtures on the nova extreme 2 bulb have bad reflectors, then the PC lights Kevmo is talking about (I have the same exact one) have TERRIBLE reflectors. 

Like i said I just upgraded from the PC kevmo's talking about to the Nova extreme 2x24 watt (24 inch). The reflectors on the Nova leave a little under a half inch of space on either side of each bulb for light to escape, which includes a reflector in the middle to separate the bulbs from reflecting into each other.

Hoppy what is an example of your opinion of good reflectors if the Nova extremes are not so good?


----------



## tom855

So here is something that's rather basic but is giving me a fit. I have two HOT5's about three inches above the glass putting the substrate about 20" below the lights. I have my spray bar at the top right of the tank, and a piece of wood that reaches up from the substrate to a point ending about an inch below the water line.

My wood is a beautiful example of light intensity vs. distance. At the bottom of the tank the wood looks like wood. The closer you get to the top the more it is covered in a thick blanket of BBA. The spray bar has the same crap on it.

My question is basic. If light falls off w/ distance squared, doesn't that mean there is a huge amount more light falling on taller stem plants than the ground cover plants? How do you deal with that? According to the chart, a single HOT5 has a PAR of about 65 at 20", but >250 at 10"!!! So what might be a good light level at the bottom is blazingly high at halfway up the tank.

How does one deal with that? Or don't they. 

FWIW, I'm finding BBA all over my plants including the ground cover, which tells me that 2 HOT5s is almost too much for a tank that is 20" deep. Interesting, that's exactly what I'm seeing. BBA all over the place.

Could it actually be that a single HOT5 is enough to put medium to high light into a 20" deep tank????? That's amazing!

This might drive me nuts enough to actually invest in a PAR meter and do these measurements just to see what's really up with this fixture at different places in the tank.

.

.


----------



## offpath

Raising the light higher off the top of the tank and increasing the intensity to compensate will give you much more even lighting. Here's a recent thread discussing exactly this:
http://www.plantedtank.net/forums/lighting/118454-light-height-above-tank.html


----------



## tom855

Great thread you referenced about light variation vs. height. 

Thanks!

.


----------



## Hoppy

Buc_Nasty said:


> If those fixtures on the nova extreme 2 bulb have bad reflectors, then the PC lights Kevmo is talking about (I have the same exact one) have TERRIBLE reflectors.
> 
> Like i said I just upgraded from the PC kevmo's talking about to the Nova extreme 2x24 watt (24 inch). The reflectors on the Nova leave a little under a half inch of space on either side of each bulb for light to escape, which includes a reflector in the middle to separate the bulbs from reflecting into each other.
> 
> Hoppy what is an example of your opinion of good reflectors if the Nova extremes are not so good?


Good reflectors look a lot like the AH Supply reflectors, with multiple bends, plenty of room on each side of the bulb for light to get around the bulb, and highly polished Miro 4 material. T5 reflectors don't need to be as wide as the AH Supply reflectors, but I think they should still be about 3X the bulb diameter, or about 2 inches wide. One thing typical of really good reflectors is that you can see several bulbs when you look up at the reflector with a single bulb installed. Each image you see of the bulb is a light path for more light to get to the tank. Even a simple DIY reflector lets you see two images, one on either side of the bulb, plus the bulb itself.


----------



## Jim Miller

I'm planning a 75g and due to the width of 18" am planning to use ICECap clip-on reflectors on 4 T5NO bulbs to give good uniformity and medium to high light which I could modulate down if necessary by turning one off and spreading them out a bit.

Has anyone got an idea for what sort of single lamp case these could be retrofitted into? 

I'm open to either leg style or sit on glass style mounting.

TIA

Jim


----------



## CptanPanic

Hoppy,
Can you add columns in your light type chart showing LED's at the different heights using data from your LED chart.


----------



## Hoppy

CptanPanic said:


> Hoppy,
> Can you add columns in your light type chart showing LED's at the different heights using data from your LED chart.


LEDs are just too complicated to do that. They produce a narrow beam of light, so if you measure the intensity a little bit off the center of that beam the intensity is very low. That means with an array of 20 LEDs spaced 4 inches apart, for example, the intensity anywhere in the tank does not drop with the square of the distance from the light - the farther you are from the array of LEDs the more of them are lighting the area and the closer you get to the array the more likely that only 4 or less are lighting the area. 

You can mount the LEDs an inch apart, 2 inches, 4 inches, etc. and each array of LEDs will give vastly different PAR readings at any distance from them. Also, you can operate them at 150 mAmps up to 1000 mAmps, getting vastly different results. The LED charts were the best I could come up with for characterizing that type of light.


----------



## Buc_Nasty

For everyone reading the thread and Hoppy's info, specifically about T5's, I just want to emphasize the importance of GOOD REFLECTORS!!!!!!!!

I've been reading a lot of the data Grim Reefer collected at Reefcentral about lighting as well, and the reflectors make all the difference.

I bought the Current Nova Extreme before I knew the importance of good reflectors...it has really crappy ones that they call "individual" for each bulb but are barely even better any old T5 light. It also doesnt have any type of cooling and a bad ballast so the lights won't last nearly as long. 

I wrote a post comparing the Nova Extreme to the Coralife Power Compact lamps earlier, which is still partly true...the T5's are a LOT better than PC, but T5's with great reflectors are a LOT better than the Nova Extreme. They are also a lot more expensive, even for just a retrofit kit.


Now I'm upgrading with the LET retrofit kit from reefgeeks with the parabolic reflectors. They will be essentially just as good as the ATI fixtures but for a whole lot cheaper.


----------



## tom855

*Coralife T5 Data*

Decided to try out my new PAR meter on a fixture I had sitting around. It's a 36" Coralife T5 (not HO). The fixture and the 6700K bulb have been used for about 4 months, so it should be well after the bulb and ballast burn in period. Data is as follows:

6" 42
12" 19
18" 11
24" 8
30" 6
36" 5


Shows that for those of us used to HOT5s, the regular T5s really don't put our a lot of light. Might be nice to add a touch more light in a particular application, but certainly not a ton of light.

Just wanted to pass the data along.

Tom 

.


----------



## Hoppy

tom855 said:


> Decided to try out my new PAR meter on a fixture I had sitting around. It's a 36" Coralife T5 (not HO). The fixture and the 6700K bulb have been used for about 4 months, so it should be well after the bulb and ballast burn in period. Data is as follows:
> 
> 6" 42
> 12" 19
> 18" 11
> 24" 8
> 30" 6
> 36" 5
> 
> 
> Shows that for those of us used to HOT5s, the regular T5s really don't put our a lot of light. Might be nice to add a touch more light in a particular application, but certainly not a ton of light.
> 
> Just wanted to pass the data along.
> 
> Tom
> 
> .


Is this with just one bulb? Plotting those data points on log-log paper, they are close to following an inverse square relationship, better than some data I have, and worse than other data. This is the first T5NO data I have received. More will be great!


----------



## tom855

Yep, single bulb. If I had more time I would have plotted it w/ Excel to take a look. Glad it makes sense.

I'm also finishing up my measurements on my 2x39W T5HO from Nova Extreme, and my Ott Lights that are for my Mini-M. Fascinating subject, I must say. I'm learning a ton and my finally be able to get things on track with my tank. It's great to really know what's going on in regards to lighting.

Tom 


.


----------



## Jim Miller

What sort of a reflector was used for this test? I would have expected about half the T5HO value. I wonder why so low?

thanks
jim


----------



## S&KGray

Jim Miller said:


> What sort of a reflector was used for this test? I would have expected about half the T5HO value. I wonder why so low?
> 
> thanks
> jim


Most likely due to the poor reflector on the Coralife fixture.


----------



## tom855

It's the standard u-shaped silver reflector that ships with the fixture.

I'm starting to be a big believer in the idea that different reflectors have a huge influence on output. I'm just finishing up my measurements on my Nova Extreme 2x39W HOT5 that are so surprising (to me) that I've decided to take them again. More to post on that topic soon.

Tom 

.


----------



## Hoppy

tom855 said:


> Yep, single bulb. If I had more time I would have plotted it w/ Excel to take a look. Glad it makes sense.
> 
> I'm also finishing up my measurements on my 2x39W T5HO from Nova Extreme, and my Ott Lights that are for my Mini-M. Fascinating subject, I must say. I'm learning a ton and my finally be able to get things on track with my tank. It's great to really know what's going on in regards to lighting.
> 
> Tom
> 
> 
> .


Just to be sure: is this a standard 2 bulb Coralife T5NO fixture, or a single bulb fixture? If it is a 2 bulb fixture, with just one bulb installed, is it possible that the single bulb is under powered as a result?


----------



## tom855

To clarify, this is a single bulb fixture, T5 NO.

.


----------



## plantbrain

I just remeasured and adjusted my tank's lighting.

My 120 Gal has about 41" from light to sediment, 1.8W/gal of T5, and the PAR is 30-34 micromols even with wood etc in the way.

My 60 Cube now *has 0.8 w/gal and similar PAR, at about 37" distance.*

Now.......30-35micromols should grow most plants fairly well.

I strongly urge folks to measure and re evaluate their (too) high intensity lighting and consider using much less, you simply are causing headaches for yourselves and the myth of the need for high light.

Note:
All values are at the sediment and in real tanks with water, wood etc.

Regards, 
Tom Barr


----------



## irbenson

Just to clarify...based on the chart, just one 54 watt T5HO bulb on a 75 gallon tank(21 high, rounded down to 20") will be medium light?


----------



## Hoppy

irbenson said:


> Just to clarify...based on the chart, just one 54 watt T5HO bulb on a 75 gallon tank(21 high, rounded down to 20") will be medium light?


Yes, it will be medium light directly under the bulb, but a 75 gallon tank is 18 inches from front to back. That is a lot of distance to expect a single bulb to adequately light. With just one bulb over the tank, the plants will all grow towards that bulb, so tall plants will look very abnormal. And, with a single bulb, any tall plants will shade low plants enough to prevent them from growing normally. If you had a pair of bulbs, widely separated, sitting right on the tank, and you ran one bulb for half the photoperiod and the other for the other half, you could avoid those problems.

Much better would be a light with multiple bulbs, raised high above the tank, giving the light room to spread out, but keeping the intensity down because of the added distance. And any light fixture that keeps more space between the bulbs will work better than one that keeps them clustered close together. If you had a 4 bulb fixture, you could raise it to about 26 inches from the substrate, and run two bulbs for the first half of the photoperiod, and the other two for the second half, and still get medium intensity.


----------



## irbenson

Hoppy said:


> If you had a pair of bulbs, widely separated, sitting right on the tank, and you ran one bulb for half the photoperiod and the other for the other half, you could avoid those problems.


Could I just slide the fixture back and forth? I wouldn't mind getting a fixture that could hold 2 bulbs but they wouldn't be widely separated from each other so I would probably still need to utilize the "sliding back and forth" thing(assuming that even works...). And I'm afraid raising the lights will make the lights pour throughout my small bedroom too much.

Thanks for the help


----------



## Hoppy

irbenson said:


> Could I just slide the fixture back and forth? I wouldn't mind getting a fixture that could hold 2 bulbs but they wouldn't be widely separated from each other so I would probably still need to utilize the "sliding back and forth" thing(assuming that even works...). And I'm afraid raising the lights will make the lights pour throughout my small bedroom too much.
> 
> Thanks for the help


Sliding the fixture back and forth would certainly work. But, are you really going to do that every day, day after day, after day.....? When you raise a light fixture, with good reflectors, only a few inches, there shouldn't be a large spillover of light into the room, especially with an 18 inch deep tank.


----------



## farmhand

irbenson said:


> I wouldn't mind getting a fixture that could hold 2 bulbs but they wouldn't be widely separated from each other...


If you buy from Catalina, for little or no extra they will mount 2 bulbs spread in their wider unit.


----------



## tom855

*Current/Nova Test Data*

I just finished measuring my three month old 36" HOT5 Nova Extreme 2x39W fixture. This is the newer model, not the one that was retired about two years ago. I have one of those also, but didn't do any measurements with it. The one tested is the one that is about 5 1/2" front to back and about 2" tall.

All measurements are done with a new Apogee MQ-200 in air, not under water. The fixture and bulbs had a 30 minute warmup before measuring. 

My first set of measurements looked awful, which led me to discovering my 5 month old AquaticLife Rosette was shot. Not so impressed with that bulblife I dare say. So, I replaced it with a new Aquasun. Measurements are with a single Current 10K (about 9 months old) and a brand new Aquasun. This should put the ballast and the 10K well past their burn in time, but the Aquasun was new.

Personally I found the results surprising:

Distance --- 10K Only --- 10K + AquaSun

6" --- 128 --- 208
12" --- 64 --- 108
18" --- 40 --- 60
24" --- 25 --- 25
30" --- 18 --- 18
36" --- 14 --- 14


What does this tell me? The Nova fixture is weak compared to some of the other fixtures that have been discussed here. I have been a fan of these fixtures for a long time, primarily because of their appearance and the fact you can run them without a fan. But, they sure don't pump out the light some of the other fixtures do. I've also had some ballast failures that have made me less than happy. But the killer for me is the lower light output, or lack thereof. 

The other things that is blazingly clear when you actually do the measurements is now much light is present as the higher levels in the tank. I'm about 20" from light to substrate, and although that has me in the 40-50 um range at the substrate, it's well over 200 at my tall plants that are approaching the top of the tank. I know this subject has been covered by other threads, but my next task is to make a hanger for a light, and then buy a light that allows me to have 20-40 on the bottom without scorching the top. The only way to do that is to up the light and then hang it over the tank to get to that shallower part of the curve. 

Thanks Hoppy for kicking off this thread. It's allowed me to look at lighting in a whole new way. And, with some persistence, allow me to the get my tank to a calm state of medium/slow growth. 

I hope the numbers help!

Tom 

.


----------



## tom855

*A question......*

So I think this thread gives some fantastic ideas, but I could really use some advice on something.....

I'm planning to buy a new fixture, and will plan on hanging it above the tank. I'd like to accomplish two things:

1) I'd like to end up in the 30-35um range on my substrate. From the top of the tank to the substrate is 20". 

2) I'd like to stay in the part of the light intensity curve where I don't have a dramatic delta in light between the top of the tank and the bottom. 

I'm thinking of hanging a light about 14" above the tank, which, according to this thread, should give me somewhat over a 3x change in light intensity from top to bottom of the tank. Measurements by multiple folks on this thread agree that's going to be in the 5x range, but that's certainly better than 7x or more.

So, bottom line is I'm considering investing in a new Catalina 36" 2x39W fixture and hanging it. 

So, do you think it will provide the power at the substrate at roughly 34" from the substrate? I'm guessing it will be close, and I can change the hanging height if I'm at least close.

If I can achieve the goal of ~30um at the substrate, any guess what the light will be at the top of the tank? I'm guessing (based on my own measurements) roughly 5x that, or 150um. Does that seem too high or will that cause problems as well?

Does the Catalina seem like a good fit? Jose's measurements seem to suggest that it's a good choice.

Thanks again, and I appreciate all of your awesome advice!

Tom 

.


----------



## plantbrain

The Tek clearly was superior to the Current brand in most all aspects IME.
Higher grade stuff can be directly measured and then justified.

I like the Gieseman bulbs, nice colors and good performance.


Regards, 
Tom Barr


----------



## tom855

Tom,

After putting a lot of $$$ in to Current/Nova over the years, I have to agree. 

Expecting that I'm only going to need a two bulb fixture to accomplish what I'm trying to accomplish, it seems like the Catalina fixture at less than half the price would make more sense. Any reason in your opinion to stay away from the two bulb Catalina given the light levels I'm shooting for?

Thanks!

Tom 

.


----------



## plantbrain

They are actually local and will build to suit.
I have not used them for one main reason: the hoods are ugly, and aesthetics are important to me.

Others with a PAR meter might be able to comment.

I test when convenient, I do not go looking for various hoods to measure.
I'd rather good look for hardscape materials, wood, etc........

Regards, 
Tom Barr


----------



## UDGags

First off awesome post Hoppy, thanks! 

I am setting up a new tank (my first tank :red_mouth) 125g (72" long x 18" wide x 24" tall) and it will have CO2. My plan is to hang the lighting ~16" above the tank so ~40" distance from the light to the substrate. After reading this forum and doing research I think I am settled on getting two SUN SYSTEM® TEK-LIGHT™ HO T5 - 34 FLUORESCENT LIGHTING FIXTURE 3' - 4 LAMP (36" L X 12" W X 2.5" H) (13,200 LUMENS) and I will hang them side by side to cover the 72".

Questions for whoever...

I think from the charts I need 2-4 bulbs, so that's why I chose 4 Lamp. Does this seem correct?

Will the 12" width on the lights be okay? or should I look at the 6 lamp (16" wide) or 8 lamp (20" wide) and just not use all the bulbs?
If anyone has any other suggestions on brand type or a different fixture I'm open to ideas/help. I'm not worried about cost, I just want it to be done right.


----------



## Seattle_Aquarist

Hi All,

A new player in town; AH Supply T5HO linear! I hope to see them in operation at Erik Olson's in the near future! Prices seem competitive.


----------



## Hoppy

Seattle_Aquarist said:


> Hi All,
> 
> A new player in town; AH Supply T5HO linear! I hope to see them in operation at Erik Olson's in the near future! Prices seem competitive.


Very good information, and good prices too! You could use two one bulb kits, and have separate switches for each bulb, not always easy to get with T5 lights. But very nice for 55 and 75 gallon tanks.


----------



## Seattle_Aquarist

Hi All,

I stopped by Erik Olson's today and saw the new AH Supply Linear kits. They look like the pictures on the website, it was interesting to note that the ballast in the kit was the Fulham Racehorse not the Workhorse ballast. Why would they use a Racehorse ballast?


----------



## Cottagewitch

How do the standard 15w fluorescent tubes that come in the standard 10g aquarium kit stack up? They aren't PC's...just standard fluorescent. I would imagine they are pretty low par right?


----------



## Cottagewitch

Another question....I've read that actinics, and certain other bulbs, don't really do anything for plants. But do they still add to the overall light levels? I'm trying to figure out ways to tone down the light coming from my 4X24W fixture before I dare put it over a 10g.


----------



## HolyAngel

tom855 said:


> Personally I found the results surprising:
> 
> Distance --- 10K Only --- 10K + AquaSun
> 
> 6" --- 128 --- 208
> 12" --- 64 --- 108
> 18" --- 40 --- 60
> 24" --- 25 --- 25
> 30" --- 18 --- 18
> 36" --- 14 --- 14


That also tells me that the aquasun bulb isn't penetrating beyond ~20" or so and useless for reaching the bottom of a 24"+ Tall tank 

Thanks for the measurements tho!


----------



## Hoppy

Cottagewitch said:


> How do the standard 15w fluorescent tubes that come in the standard 10g aquarium kit stack up? They aren't PC's...just standard fluorescent. I would imagine they are pretty low par right?
> 
> Another question....I've read that actinics, and certain other bulbs, don't really do anything for plants. But do they still add to the overall light levels? I'm trying to figure out ways to tone down the light coming from my 4X24W fixture before I dare put it over a 10g.


Those 15 watt fluorescents are T8, so the chart covers them.

Actinic bulbs do add more PAR so they will help plants to grow, but the visual effect is so weird most people don't like them for a planted tank.

The best way to use the 4 x 24 watt T5HO fixture on a 10 gallon tank is to use only two of the bulbs, and suspend it about 10-12 inches above the top of the tank. You could also use a layer of fiberglass "insect screen" between the bulbs and the tank, which would let you use the fixture about 6 inches above the top of the tank.

Why not just sell the fixture and get a light that is more appropriate for a 10 gallon tank?


----------



## Hoppy

HolyAngel said:


> That also tells me that the aquasun bulb isn't penetrating beyond ~20" or so and useless for reaching the bottom of a 24"+ Tall tank
> 
> Thanks for the measurements tho!


If it isn't "penetrating" beyond 20 inches why does the PAR meter read 14 at 36 inches?


----------



## plantbrain

http://www.ahsupply.com/54wInstalls.htm

For folks with wood type hoods, this 2 bulb configuration is all you might ever need for most tanks up to 75Gal.

Certainly not more.
Ideally, you'd be able to have each bulb on a timer.

Even 1x 54 W on a 55 gallon tank is enough to grow most plants.

I use 2x 24 w at 1 meter distance from the sediment bottom and am getting 30-35 micromols.

20-25 are the lower limits for many species.
40-50 is optimal for most

Regards, 
Tom Barr


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## S&KGray

Hoppy said:


> If it isn't "penetrating" beyond 20 inches why does the PAR meter read 14 at 36 inches?


I think HolyAngel deduced that the Aquasun bulb doesn't penetrate beyond ~20" in the Current fixture because the PAR readings with the Current 10K bulb only and the PAR readings with the Current 10K + Aquasun are the same starting at 24". It does look like the Aquasun isn't contributing any PAR from 24" on when considering those PAR readings.


----------



## fischman

S&KGray said:


> I think HolyAngel deduced that the Aquasun bulb doesn't penetrate beyond ~20" in the Current fixture because the PAR readings with the Current 10K bulb only and the PAR readings with the Current 10K + Aquasun are the same starting at 24". It does look like the Aquasun isn't contributing any PAR from 24" on when considering those PAR readings.


This makes me wonder about the filtering qualities of water. By using bulbs with higher peaks in the blue wavelengths will you avoid as much filtering as you might using lights with higher wavelengths such as yellows and reds? I know that water lets blue light through better than others, hence why deep water looks bluer than shallow water. What kind of issues could we run into with deep tanks with lights that can't pass through to the bottom and are there any benefits to using bulbs that can provide a more consistent light quantity regardless to depth? 

Josh

Edit: To add to my previous post, I see he made those measurements without water. What additional effects would water make on the filtering of certain wavelengths. I've heard that water actually increases the PAR due to reflections and what not. But on a deep tank of water how much are the red and other wavelengths affected when compared to the blue wavelengths. 

This could also explain why some people have algae problems when switching to Actinics, if more light is actually reaching deeper into the tank they could be increasing their lighting rather than just swapping bulbs even if it doesn't appear to be brighter.

Josh


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## Hoppy

Two feet of water absorbs little light in any part of the spectrum except for the red end. It isn't the absorption by water that dims the light in a high tank, it is the distance from the light that causes almost all of the loss in intensity. And few planted tanks are higher than 2 feet.


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## Sluggo

I get what you're trying to do here, but I'm still struggling with the idea that my 65-watt Coralife CF fixture over a 20H equals "low light." Although, it _would_ explain a few things.

Do AHS reflectors fit into Coralife fixtures?


----------



## Jeff5614

I've been reading this thread over and over for quite a while now trying to wrap my head around the idea that I would be fine with less light. When I first started a planted tank it was a 55 with 2x65 PC. After getting the CO2 dialed in, which pretty much consisted of just putting the diffuser in the tank, the tank took off. It seemed like there was nothing I couldn't grow other than a couple of species. I read threads about algae issues others were having and wondered what is this thing called algae, lol. I had some GSA on the glass but that was it, no GDA, no BBA. 

Then my ballast blew and I decided I would upgrade to T5HO. I would be moving from a 55 gallon to a 75 soon so I knew based on everything I had read that I'd not be able to grow much in it with the same PC fixture and everyone was talking about how great they were so I had to get one. I fired it up and wow, 4x54 was a lot of light. The plants pearled like crazy and within a few days I was learning what GDA was. So I backed down to 2x54 which was still noticeably quite a bit brighter than the PC fixture I had replaced. 

Since switching to T5HO's a couple of years ago I've learned all about BBA and GDA first hand. I've learned it's a real tightrope act trying to balance the amount of CO2 needed for me to avoid algae issues with 2x54 sitting 20 inches over the substrate. When I look at Hoppy's chart I see that my PAR values are higher with one T5HO bulb than they were with two PC bulbs. 

As of today, I'm cutting back to 1x54 over my 75 other than a 3 hour period using 2x54. Going cold turkey on high light isn't going to be easy. I look at the tank and it looks too dark to me now and I want to walk over and flip on the other bulb, but I remember how easy the 55 with less light was. So it will be interesting to see how things go.

Here's a pic of the old 55 with a PAR value of 30 at the substrate based on Hoppy's chart. Not a masterpiece by any means, I was a noob with even less scaping ability than I have now, lol, but it was algae free and easy to keep up.


----------



## tom855

Jeff,

Your story is amazing, and I think it's pretty much my world as well. I've been struggling with algae for years, and I sincerely believe it's related to the lighting issue. I finally invested in a PAR meter, and I'm about to make some major lighting changes myself. I'm going to buy a fixture that can switch on either one, two or three bulbs at a time, and I'll be suspending it well up over the tank. I may not even opt for the third bulb. I'm not sure there would ever be a need for it. 

Your old tank is great looking. Any guess (from the charts) what your PAR reading was at the substrate? Did you have your light on 4" legs above the top I assume?

Thanks for sharing the great information!

Tom 

.


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## Jeff5614

oops, duplicate.


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## Jeff5614

> ...Any guess (from the charts) what your PAR reading was at the substrate? Did you have your light on 4" legs above the top I assume?
> 
> Thanks for sharing the great information!
> 
> Tom


It sat on the rim so it was around 20 inches or so over the substrate and based on Hoppy's chart would have had a PAR value of around 30.

Let me know if you ever decide to start renting or loaning out that PAR Meter .

BTW, I bought a 2x54 from Catalina Aquarium and had each bulb wired separately with separate switches and they did it for no additional charge.


----------



## tom855

Jeff,

Our tank dimensions (mine's a 58G) are the same except mine is 36" where yours is 48", and I would have to agree. I've tried a bunch of different things over the past few years, most involving 2 HOT5 bulbs sitting on or very close to the top of the tank. Looking at the charts that ranges from really high light at the substrate to blinding light near the top of the tank. 

I've been thinking a lot about this thread, and really am wondering if hanging the fixture higher will fix some of the problems. At the least, it will make the light a bit more consistent from top to bottom. 

Regarding the Catalina, I've been thinking about making the same investment. Knowing they will make things custom, I was considering asking them to take a 4 fixture unit and install 3 bulbs on two ballasts. I was going to have the single bulb in the center position so that if I use just one bulb it's always over the middle of the tank, and if I have two bulbs on those two are also centered over the tank. By buying a two light version it seems either the single or the double is going to be off center. Have you had any problems with that? 

Also, I was thinking that since suspending the fixture was an option, having two or three bulbs available might be helpful. The ONLY thing that concerns me about hanging a fixture (besides the DIY hassle), is the fact that it's going to light up the wall behind the tank which might look nasty and when I sit in the room with the tank, the darn light will be in my eyes when I look at the tank. Not sure how to proceed there. Who knows - maybe a single T5 sitting on the tank is a nicer looking option.

Regardless, it's clear that much of the lighting I've been using is overkill. I think it's time to back things off and as you said, "resist the temptation to walk over and flip on the other bulb."

Tom 

.


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## Jeff5614

Being able to hang the fixture and adjust the height over the tank as needed seems like the best option but I do understand the concern with light spilling into the room. Mine is under a canopy and the most I can raise it is 4 inches over the tank. Hanging it will lower the intensity in the top of the tank and seems it would give you a more consistent intensity through the depth of the tank. I'd really like to be able to try it myself.

If you're going to hang it, then as Plantbrain mentioned aesthetics are something to think about. While Catalina makes a well priced customizable fixture, there are other more aesthetically pleasing lights, just ask my wife, lol. I'd look into a Tek fixture or an ADA fixture (pricey) or something similar in appearance to either.


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## crf529

Hey Hoppy, i'm looking at starting a 12G long, so top of the tank about 8" from the substrate, but T5NO bulbs are virtually non existent here so looks like ill have to go T5HO. I'm keen to get the light as close to the tank as I can, and for medium lighting I think about 11" or so from the top is as close as I can comfortably put it. Do you have any info on how much the intensity would be reduced by using some flyscreen mesh to shield the bulb? I though I might have read somewhere that it reduces intensity by 30-40% but cant find the thread or any other info.


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## tom855

*T8 Single Strip PAR Measurements*

I just took some measurements on the 36" Single Strip T8 Fixture from Oceanic I had sitting around. It's a couple of years old but only was unused. Measurements were as follows:

6" -- 73
12" -- 41
18" -- 25
20" -- 23
24" -- 18
30" -- 12
36" -- 9


What does this tell me? It tells me I'm going to try to find myself a two tube version of the same light. IF I can find it, and it measures to be about twice the numbers above, I'll have finally found the light I'm looking for. That would put about 45-50um on the substrate and no more worrying about hanging a fixture, scorching my plants, and enhancing my algae farm. 

I love my T5HOs. They are sleek, cool, quiet and I have a dozen or so different bulbs floating around. Unfortunately I think they all overkill for the light levels I really NEED.

If anybody has any PAR measurements for an All Glass twin tube T8 I'd love to see them. 

Thanks!

Tom


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## Hoppy

crf529 said:


> Hey Hoppy, i'm looking at starting a 12G long, so top of the tank about 8" from the substrate, but T5NO bulbs are virtually non existent here so looks like ill have to go T5HO. I'm keen to get the light as close to the tank as I can, and for medium lighting I think about 11" or so from the top is as close as I can comfortably put it. Do you have any info on how much the intensity would be reduced by using some flyscreen mesh to shield the bulb? I though I might have read somewhere that it reduces intensity by 30-40% but cant find the thread or any other info.


When I measured the effect of Home Depot fiberglass "insect screen" it reduced the PAR readings by about 40% for one layer, and, as I expected, by about 64% with two layers.


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## crf529

Thanks very much! And just out of curiosity, whether I attach the screen to the fitting or put it on the top of the tank as a lid to prevent jumpers, it should yield pretty similiar reductions in PAR when the fitting id only about 6-7" above the rim of the tank?


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## tom855

*Ott Light PAR Measurements*

I measured two different Ott Lights (13W) that I plan to use on my upcoming Mini-M. Measurements on both were close, but because of their size I only took two data points on each. They were in air, not water, as my tank isn't set up as of yet.

6" from bulb - 70um
12" from bulb - 19um

The 12" measurement is probably the most meaningful, as that's very close to where the substrate on a 5.5g tank would be. Shows that a single light is probably not enough for that size nano, and two would be just about right. We'll see if that's how it works out in real life.

It's interesting to note that two of these fixtures would provide over 5 WPG, but still only put 40um on the substrate of a 5.5G. This of course backs up with data what many folks already know, that you need more WPG in a smaller tank. 

Hope the numbers are of interest.

Tom

.


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## Hoppy

crf529 said:


> Thanks very much! And just out of curiosity, whether I attach the screen to the fitting or put it on the top of the tank as a lid to prevent jumpers, it should yield pretty similiar reductions in PAR when the fitting id only about 6-7" above the rim of the tank?


I tested this with the screen on the bottom of the light fixture, and on the top of the tank, getting the exact same PAR readings.


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## crf529

Fantastic! Cheers Hoppy, without a doubt the leading expert in aquarium lighting!


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## ddtran46

Hoppy, is 2 x 24 watt t5ho 2" over the top of a 17 gallon too much lighting?

How many inches do you recommend my light should be over my tank? (the tank is about 14" in height)


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## Hoppy

ddtran46 said:


> Hoppy, is 2 x 24 watt t5ho 2" over the top of a 17 gallon too much lighting?
> 
> How many inches do you recommend my light should be over my tank? (the tank is about 14" in height)


I would put that light about 30 inches from the substrate, to get low medium lighting. If you want to struggle with high lighting you can use it at about 22 inches from the substrate.


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## Aquaticz

Hi Hoppy,
Always trying to do better & your post help a heap. The query.....
I have two tanks( 55 & 75) each tank has 4 X 55 w CF lighting by A&H Supply
lights sit on top of tank and the distance from subsrtrate is
55 gal = 15"
75 gal = 22 in"
These are DIY fixtures that are 48 X 10 X 4
each fixture has 1/4" glass between the fixture & the water
I fertilize & use pressurized CO2

I originally set up for high light but I may have to much light.
I hoping you would be kind enough to tell me what I have, and also how much would I need to raise the fixture for a medium and or a low light tank ( less work more pleasure - either way) for each of the two tanks. 
Thanks for sharing what you know  it is GREATLY appreciated


----------



## ddtran46

Hoppy said:


> I would put that light about 30 inches from the substrate, to get low medium lighting. If you want to struggle with high lighting you can use it at about 22 inches from the substrate.


What type of lighting would you consider 1x24 watt t5ho 14" above the substrate in a 17 gallon tank?


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## offpath

ddtran46 said:


> What type of lighting would you consider 1x24 watt t5ho 14" above the substrate in a 17 gallon tank?


If you look at the chart on the very first post of this thread, you'll see that 1 T5HO 14" above the substrate should be about 130 micromols of PAR, which above the range that Hoppy has listed as "high" light. You can use that chart to figure out how high you should raise that fixture to get the desired light level.


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## ddtran46

offpath said:


> If you look at the chart on the very first post of this thread, you'll see that 1 T5HO 14" above the substrate should be about 130 micromols of PAR, which above the range that Hoppy has listed as "high" light. You can use that chart to figure out how high you should raise that fixture to get the desired light level.


Yeah I saw that but is 24 watts of t5ho over a 17 gallon really high light? Does the wpg rule apply to this?


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## MarkMc

ddtran46 said:


> Yeah I saw that but is 24 watts of t5ho over a 17 gallon really high light? Does the wpg rule apply to this?


With T5 HO the watt per gallon rule is not too helpful. T5 HO's with a good reflector are very bright lights. I would estimate my fixture to be close to 3 feet above the substrate (T5-HO).


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## Herbicidal

I borrowed our clubs PAR meter (thanks Tom Barr of the Sacramento Aquatic Plants Society!) and set the sensor at the bottom of the aquarium on top of the substrate. The distance from the substrate to the lights in the canopy is 29 inches. I have two sets of 2 bulbs (39 watt) Catalina retro-fit units. The are placed end to end and run the length of the tank mounted in the canopy. Like this:









The measurement on the meter showed me 029. Sorry for my ignorance, but is this the PAR level as indicated on the vertical side in Hoppy's 1st post? If so, then I am in the low light range, which is what I thought. However, on Hoppy's graph it says "For 2 to 4 bulb T5HO fixtures, multiply PAR by the number of bulbs". If that's the case, then would I multiply 029 x 4 bulbs? That would give me a 116 PAR, which according to the graph would put me at the top of the high light range. :icon_eek: That can't be right... Someone please help set me straight! Thanks!


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## S&KGray

Hoppy is referring to the value for T5HO on his graph which is for one bulb, so if you have more bulbs then you would multiply. This is when using his graph for estimating your PAR using the data he collected.

You are measuring your PAR so whatever PAR you measure is what PAR you have within tolerances of the meter you are using.

Edit: I just looked at the graph again and it estimates around 30 PAR for 1 T5HO bulb at 29 inches. I see your confusion, when multiplying by 2 (2 bulbs wide, the 2 bulbs end to end count as one long bulb) the graph indicates you should have around 60 PAR. When you measure you have a PAR of 29, meaning your fixture is putting out about half of the PAR of the fixture Hoppy measured when collecting data.

I guess this shows how variable the PAR output of different T5HO fixtures can be.


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## CptanPanic

This might not just be a case of output variability of t5ho, but maybe 2 short bulbs do not equal 1 long bulb, but are really only half as bright.


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## ubr0ke

Herbicidal... I can not tell from the pic but does your lighting have reflectors?..And also with lights running directly in the middle of course your par is going to be lower along the glass. Take another reading right below the lights.The lights should have been mounted with a 6" gap between them for better spread..


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## Herbicidal

ubr0ke said:


> Herbicidal... I can not tell from the pic but does your lighting have reflectors?..And also with lights running directly in the middle of course your par is going to be lower along the glass. Take another reading right below the lights.The lights should have been mounted with a 6" gap between them for better spread..


Hello *ubr0ke*, yes, the lights are from Catalina and have excellent reflectors built in. In hindsight, I should have requested a gap between the bulbs, just didn't know it at the time I placed my order. I believe Catalina will space the bulbs if requested, however they may cost a little more for the additional materials. I was unable to place the sensor directly under them due to plants/driftwood in the way. From playing around with it a little bit, such as moving it closer to the driftwood, but not blocking the light, it went up to 032. So still low light, which is fine. I'm returning the meter to Tom on my way home from work tonight as he needs it by tomorrow so my 'playtime' is over for now. :tongue:


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## Zareth

I have a 20 gallon H tank that is 16'' high and 24'' wide. I'm going to hang the 36'' hagen glo fixture above it, its the double bulb fixture. Each bulb is 39 watts - overkill I know - I'm dumb, but if I get a bigger tank in the future I want to be able to use it. 

How high would you say I should hang this light? I wouldn't be opposed to 1-2 feet if that will keep me in the medium to high range. Really medium would be ideal, I don't want to have to fertilize non stop. If a single t5 4 inches over a 16'' deep tank is medium light, a double bulb t5, which is a full foot wider than the tank, should most definitely put me in high or too high at that height, correct?


----------



## mistergreen

Herbicidal said:


> Hello *ubr0ke*, yes, the lights are from Catalina and have excellent reflectors built in. In hindsight, I should have requested a gap between the bulbs, just didn't know it at the time I placed my order. I believe Catalina will space the bulbs if requested, however they may cost a little more for the additional materials. I was unable to place the sensor directly under them due to plants/driftwood in the way. From playing around with it a little bit, such as moving it closer to the driftwood, but not blocking the light, it went up to 032. So still low light, which is fine. I'm returning the meter to Tom on my way home from work tonight as he needs it by tomorrow so my 'playtime' is over for now. :tongue:



yeah, it's definitely your spacing and reflectors... And from the picture, your PAR sensor is slightly tilted too.. You'd be surprised at the variance in readings from variance in the angle.. I bet you can get an extra 10 - 20 PAR if you pointed the sensor straight at the light.


----------



## Hoppy

Aquaticz said:


> Hi Hoppy,
> Always trying to do better & your post help a heap. The query.....
> I have two tanks( 55 & 75) each tank has 4 X 55 w CF lighting by A&H Supply
> lights sit on top of tank and the distance from subsrtrate is
> 55 gal = 15"
> 75 gal = 22 in"
> These are DIY fixtures that are 48 X 10 X 4
> each fixture has 1/4" glass between the fixture & the water
> I fertilize & use pressurized CO2
> 
> I originally set up for high light but I may have to much light.
> I hoping you would be kind enough to tell me what I have, and also how much would I need to raise the fixture for a medium and or a low light tank ( less work more pleasure - either way) for each of the two tanks.
> Thanks for sharing what you know  it is GREATLY appreciated


At 15 inches from the substrate, you have about 150 micromols of PAR, very high light - too much. Raise it to about 22-24 inches from the substrate for medium light, or to about 25-27 inches from the substrate for low light. I'm assuming the bulbs are mounted in two rows, each with two bulbs. If you keep the glass clean, it shouldn't have much effect on the light intensity.


----------



## Hoppy

Herbicidal said:


> Hello *ubr0ke*, yes, the lights are from Catalina and have excellent reflectors built in. In hindsight, I should have requested a gap between the bulbs, just didn't know it at the time I placed my order. I believe Catalina will space the bulbs if requested, however they may cost a little more for the additional materials. I was unable to place the sensor directly under them due to plants/driftwood in the way. From playing around with it a little bit, such as moving it closer to the driftwood, but not blocking the light, it went up to 032. So still low light, which is fine. I'm returning the meter to Tom on my way home from work tonight as he needs it by tomorrow so my 'playtime' is over for now. :tongue:


It is very hard to get a good reading on a light when there are plants, wood, etc. in the way. They shade the sensor, and that drops the reading very fast. Of course, that's what you actually have in a planted tank, but there is no way to even guess how much light someone has below a thicket of vals, or some hairgrass, or some big sword plants, etc. About all you can do is measure the intensity in a bare tank, then by spacing the bulbs farther apart you eliminate some of the shading, and by keeping the plants pruned to avoid an overgrown jungle, you avoid the severe shading of the lower plants.

I'm not sure if Catalina has always used the same design reflector, nor whether their retrofit kits use the same ones as the ones they build. I do know that the bulbs need to have an inch or so gap between them in order to get the best output from the bulbs. The Catalina fixtures that I had data from, which were included in my data collection, gave about the same light as the more expensive light fixtures.

I notice that you had the sensor pretty close to the front glass of the tank, far from the center of the tank. The light intensity does drop quite a bit that far from right under the bulbs. It doesn't drop that much, but I suspect the plant leaves far above were also shading the sensor.


----------



## Hoppy

Zareth said:


> I have a 20 gallon H tank that is 16'' high and 24'' wide. I'm going to hang the 36'' hagen glo fixture above it, its the double bulb fixture. Each bulb is 39 watts - overkill I know - I'm dumb, but if I get a bigger tank in the future I want to be able to use it.
> 
> How high would you say I should hang this light? I wouldn't be opposed to 1-2 feet if that will keep me in the medium to high range. Really medium would be ideal, I don't want to have to fertilize non stop. If a single t5 4 inches over a 16'' deep tank is medium light, a double bulb t5, which is a full foot wider than the tank, should most definitely put me in high or too high at that height, correct?


I think about 10-12 inches above the top of the tank, or about 26 inches from the substrate, would give you medium light. (The extra foot of bulb length just lights up the floor, not the tank.)


----------



## Zareth

Hoppy said:


> I think about 10-12 inches above the top of the tank, or about 26 inches from the substrate, would give you medium light. (The extra foot of bulb length just lights up the floor, not the tank.)


Alright thanks, I figured with the light raised up a wider bulb would produce more PAR from the light waves overlapping. But perhaps the light waves do not travel out in a cone


----------



## tyronegenade

I'm jumping in here a bit late with some questions so sorry if these have already been addressed:



Hoppy said:


> Since I have previously found that I get virtually the same readings with water in the tank and with air in the tank, I omitted the water this time.


Can we see this data? Was the water fresh or aged aquarium water like most us have? Aged aquarium water has a mix of polyphenols which absorbs red and blue light, greatly affected light transmittance. In any case, based on the light attenuation properties of pure water, after 30 cm you should loose about 50% of the red light entering the water column. There should be a large discrepancy between and air and water filled tank only some other physics is compensating. 




Hoppy said:


>


In a 62 (l) x 38 (d) cm tank I grew plants very happily with a single 15 W flourescent tube. According to this table the light level was lower than low. Over my 1.2 x 45 cm tank I have three 30 W tubes and grow Glosso, hair grass, HM and a range of plants (which at one time included Rotala macrandra). According to your table this should be a low light tank. 

Internal reflection of the light on the aquarium glass under the water level could explain how a higher amount of light can reach the substrate than expected for an air filled tank where internal reflection will not occur as much. Have you compensated for this internal reflection in your model?

We at APSA (see http://www.apsa.co.za/board/index.php?topic=4846.0) have been toying with a different model to gauge lighting. We would appreciate your comments. Hint-hint: You may notice the repeated request for more data to test our model.

Kind regards


----------



## Hoppy

tyronegenade said:


> I'm jumping in here a bit late with some questions so sorry if these have already been addressed:
> 
> Can we see this data? Was the water fresh or aged aquarium water like most us have? Aged aquarium water has a mix of polyphenols which absorbs red and blue light, greatly affected light transmittance. In any case, based on the light attenuation properties of pure water, after 30 cm you should loose about 50% of the red light entering the water column. There should be a large discrepancy between and air and water filled tank only some other physics is compensating.


I came up with that chart based on lots of data from different people, with different lights, over about a 2 year period. I manipulated the data a considerable amount, so individual data points could well fall outside of the chart. There are just far too many variables involved to exactly duplicate someone else's setup and get the same PAR numbers. My goal was to find a way to make a decision about what light fixture to use on any specific tank, not to accurately forecast the exact PAR that would be obtained for any one fixture.

If water looks clear, not colored, not cloudy, there is lots of data indicating the the loss of light intensity with distance is trivial up to 24 inches or so of depth. No question, red light is lost long before blue light is lost, but at 24 inches the loss of PAR should be too small to worry about. But, once you have tannins in the water, so it appears tinted, or once you have any haze or cloudiness, or even lots of floating specs of debris, the light loss goes up. I always presume people filter their water and replace it often enough to maintain clear, uncolored, non-hazy water.




> In a 62 (l) x 38 (d) cm tank I grew plants very happily with a single 15 W flourescent tube. According to this table the light level was lower than low. Over my 1.2 x 45 cm tank I have three 30 W tubes and grow Glosso, hair grass, HM and a range of plants (which at one time included Rotala macrandra). According to your table this should be a low light tank.
> 
> Internal reflection of the light on the aquarium glass under the water level could explain how a higher amount of light can reach the substrate than expected for an air filled tank where internal reflection will not occur as much. Have you compensated for this internal reflection in your model?


My data concerned only the area directly under the light, not close to the glass, or much off center of the tank. So, I didn't compensate for internal reflection. Based on one test I did, that reflection, plus the "focusing" of the light due to refraction at the water surface, can cause the intensity near the glass to be even greater than directly under the bulb. But, that effect is only there if the glass is always very clean, inside and out.

The way I determined that water vs. air was not a concern was by measuring PAR at various distances from the light, first with the light just a short distance above the water surface, then with the light much higher. When I plotted that data on log log paper, I could draw a straight line through the data points, without regard for how much of the optical path was in air or in water, and this was including PAR right under the water surface. The slope of that straight line was very close to -2.0, demonstrating that the intensity was inversely proportional to the distance squared, as it theoretically should be, either in air or water or a mix of the two. As you get close to the bulb, that relationship breaks down, and the increase in intensity with decreasing distance reduces a great deal. But for a typical light over a typical tank, the area we are interested in is far enough from the bulb for the inverse square relationship to be valid.


> We at APSA (see http://www.apsa.co.za/board/index.php?topic=4846.0) have been toying with a different model to gauge lighting. We would appreciate your comments. Hint-hint: You may notice the repeated request for more data to test our model.
> 
> Kind regards


I read the posts at that link you gave. I don't agree with three of the assumptions: First, because light does decrease inversely proportional to distance from the bulb, any chart has to show that, and any parameter based just on the tank surface area and bulb wattage cannot be correct. And, bulb wattage is almost irrelevant, since a 2 foot long T5HO light gives very nearly the same PAR directly under it, when it is on a 4 foot long tank, as does a 4 foot long bulb of more than twice the wattage. The shorter bulb just doesn't light up the whole tank. Similarly, a 4 foot long bulb over a 2 foot long tank, gives nearly the same PAR as a 2 foot long bulb. The intensity does drop off a bit near the end of any bulb, but this is a secondary effect. Last, the effect of the reflector is downplayed too much in your chart. A good, typical T5HO single bulb reflector can nearly triple the PAR you get from that bulb, but a flat plate reflector, made of white painted metal, doesn't even double the intensity. The easy way to demonstrate this is to look up at the bulb (turned off). With a very good reflector you see at least 3 bulbs, sometimes even 5 bulbs. Each of the "virtual" bulbs is sending light into the tank, contributing something less that that from the real bulb, but still a major contributor to the total intensity. A typical 65 watt PC bulb is also a fluorescent light, but the typical reflector for that bulb is little more than a flat plate that has to reflect around the edges of the bulb, where there is often less than a cm of clearance. When you look up at that bulb, you usually see just the bulb and a small portion of the edge of the bulb in the reflector. The amount of PAR per watt for that bulb is very small compared to a T5HO light.

Trying to figure out a way to determine the appropriate light for a given tank is very difficult, and my chart will often be incorrect, but it is still far better than anything else I have seen. I'm quite sure that as people like your group keep working on this problem a much better way will eventually be developed.


----------



## jrman83

Hoppy, I'm getting ready to buy new lights for my 125gal tank and was probably going with Catalina lights. I would like to be on the high end of medium light or maybe in the low-high light area. From the top of the tank to the substrate is 18" and I have glass canopies with 1/4" glass.

I'm going to get 2-36" inch T5HO lights (72" tank) and was unsure if to go with the 2X39watt or 4X39watt to reach my goal. If I get the 2X would that be sufficient if sitting on top of the tank? If not, will the 4X need to be elevated above the tank?

Thanks for the help.


----------



## Hoppy

That 125 gallon tank is probably 18 inches front to back depth. A single tube light right at the top of the tank would leave the upper areas away from the center of the tank considerably less bright. That would cause all plants to grow to the center of the tank, which wouldn't look too good. If you used a fixture with two rows of bulbs (4 total bulbs), but with the rows widely separated, you would avoid much of that problem. That fixture should work if you use the feet that you can get for the fixture. And, if you used a two row of bulbs fixture and suspended it about 8-12 inches above the top of the tank, you would also avoid that problem. Suspending the fixture that way also reduces the light intensity at the top of the tank so it isn't so much higher than at the bottom, also a good idea. You could use a 4 row of bulbs fixture, with a big gap between the pairs of rows, and get the best of both worlds. With that, I would plan to suspend it about 8-12 inches above the top of the tank. That, of course, is the most expensive option.


----------



## jrman83

Hoppy said:


> That 125 gallon tank is probably 18 inches front to back depth. A single tube light right at the top of the tank would leave the upper areas away from the center of the tank considerably less bright. That would cause all plants to grow to the center of the tank, which wouldn't look too good. If you used a fixture with two rows of bulbs (4 total bulbs), but with the rows widely separated, you would avoid much of that problem. That fixture should work if you use the feet that you can get for the fixture. And, if you used a two row of bulbs fixture and suspended it about 8-12 inches above the top of the tank, you would also avoid that problem. Suspending the fixture that way also reduces the light intensity at the top of the tank so it isn't so much higher than at the bottom, also a good idea. You could use a 4 row of bulbs fixture, with a big gap between the pairs of rows, and get the best of both worlds. With that, I would plan to suspend it about 8-12 inches above the top of the tank. That, of course, is the most expensive option.


Thanks for the response. Tank is 18" front to back depth.

When you say 4 rows of bulbs you mean the 8X39w, correct? If I were to go with a 72" fixture would the 6X80w be adequate for my goal?

Which fixture would you go with?


----------



## Hoppy

jrman83 said:


> Thanks for the response. Tank is 18" front to back depth.
> 
> When you say 4 rows of bulbs you mean the 8X39w, correct? If I were to go with a 72" fixture would the 6X80w be adequate for my goal?
> 
> Which fixture would you go with?


Yes, I meant an 8 x 39 watt fixture. A fixture with an 80 watt bulb in place of each pair of 39 watt bulbs would work the same. But, I shudder just thinking about trying to find 6 foot T5HO bulbs or trying to get them shipped without breakage. So, I would stick to the shorter bulbs.


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## tyronegenade

Hoppy said:


> ...I don't agree with three of the assumptions: First, because light does decrease inversely proportional to distance from the bulb, any chart has to show that, and any parameter based just on the tank surface area and bulb wattage cannot be correct. And, bulb wattage is almost irrelevant, since a 2 foot long T5HO light gives very nearly the same PAR directly under it...


Thanks for the reply, Hoppy. There is a lot to think about... Just a few things:

1. The only data I have for attenuation is the data at http://www.barrreport.com/showthrea...alues-who-knew?highlight=lighting+aqua+forest where the data fit an explanation of attenuation than the inverse square law. A friend disputed this and I convinced him to do an experiment. Again, the loss of PAR was too little to be attributed to the inverse square law but was too big to call attenuation negligible. His water was an off-yellow color as I suspect most people's tank to be.

2. The estimates are not based solely on surface area and wattage. We have a reflector efficiency model as well which projects how much light would strike the water's surface from x cm away and according to what type of reflector. So when I assume 95% reflector efficiency the distance between the water and the lamp is included.

3. Bulb wattage is irrelevant. My choice of increasing by 30 W increments is because one 30W tube straddles a 1.2 m tank very nicely. You are correct that by using a T5, metal halide or other lamp would make a difference to light distribution but Tom Barr's data says that it all evens out to wards the bottom of the tank in any case. In this respect I justify W/m2 as a good guess at PAR at a particular depth (but this guess gets weaker as the water gets shallower and the tank wider).

I will link to your post here but would appreciate your brain joining in on our discussion on APSA.

Kind regards


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## Hoppy

tyronegenade said:


> I will link to your post here but would appreciate your brain joining in on our discussion on APSA.
> 
> Kind regards


I used to be a regular at 3 different forums, but that began to consume far too much time, because I always seemed to have something I wanted to say :hihi:

Now, I limit myself to just this one, and it still takes up a lot of my time, for the same reason. I just don't want to spend all day sitting here at the computer. But, thank you for the invitation.


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## tusk

Maybe I'm just too tired to try and think about this right now, but I have been wondering about my light setup for some time. Everything in my tank should be good to go, but I just have a heck of a time getting decent growth out of it. 

This one is a custom 110 tank so things are a bit wacky.....

AH Supply PC lighting from front to back - 55w w x2, 96W, 55W, 13w (274w)
Depth from reflector to substrate - 25"

So am I reading the chart right and it's stating that this is a pretty low light tank? I wasn't expecting that. Could someone recommend a photo period?

Thanks.


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## RipariumGuy

When is a fully fledge article coming out? Really. Your work is groundbreaking. Why not share it with everybody? From a broader audience I mean.


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## Hoppy

tusk said:


> Maybe I'm just too tired to try and think about this right now, but I have been wondering about my light setup for some time. Everything in my tank should be good to go, but I just have a heck of a time getting decent growth out of it.
> 
> This one is a custom 110 tank so things are a bit wacky.....
> 
> AH Supply PC lighting from front to back - 55w w x2, 96W, 55W, 13w (274w)
> Depth from reflector to substrate - 25"
> 
> So am I reading the chart right and it's stating that this is a pretty low light tank? I wasn't expecting that. Could someone recommend a photo period?
> 
> Thanks.


Is this how the lights are arranged on the top of the tank, roughly?








If that's how it is, I think you have medium light, probably high medium light.


----------



## Hoppy

JakeJ said:


> When is a fully fledge article coming out? Really. Your work is groundbreaking. Why not share it with everybody? From a broader audience I mean.


I have thought about this, but I don't believe it is ready for prime time yet. I feel like I need more data to confirm that the charts are reasonably accurate. Meanwhile, I use those charts to get as close as I can to a good guess about what any arrangement of lights will give for intensity. I keep hoping someone else will be inspired to spend a lot more time and effort based on this framework to make the charts better. Then, they can write a more widely published article. It is a fun project, in many ways, but time consuming and if you get lots of different lights to measure PAR on, it requires that you have a lot of friends with various lights, willing to get PAR data or let you do it.

I'm always aware too, that a better treatment of lighting is very likely to be found by someone who brings some fresh insight to it.


----------



## RipariumGuy

Hoppy said:


> I have thought about this, but I don't believe it is ready for prime time yet. I feel like I need more data to confirm that the charts are reasonably accurate. Meanwhile, I use those charts to get as close as I can to a good guess about what any arrangement of lights will give for intensity. I keep hoping someone else will be inspired to spend a lot more time and effort based on this framework to make the charts better. Then, they can write a more widely published article. It is a fun project, in many ways, but time consuming and if you get lots of different lights to measure PAR on, it requires that you have a lot of friends with various lights, willing to get PAR data or let you do it.
> 
> I'm always aware too, that a better treatment of lighting is very likely to be found by someone who brings some fresh insight to it.


I hope I can follow in your footsteps. But having not started high school yet hinders what I can do. In the future though, the hobby had better look out! :icon_roll


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## tusk

Hoppy said:


> Is this how the lights are arranged on the top of the tank, roughly?
> 
> 
> 
> 
> 
> 
> 
> 
> If that's how it is, I think you have medium light, probably high medium light.


Not quite, it is a trapezoidal tank to fit into a corner.










Still feel this is med - high light? If you were to use this setup, where would you start in with a photo period? 8hrs?


Thanks.


----------



## Hoppy

tusk said:


> Not quite, it is a trapezoidal tank to fit into a corner.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Still feel this is med - high light? If you were to use this setup, where would you start in with a photo period? 8hrs?
> 
> 
> Thanks.


I think you have medium light, somewhere around 60-75 micromols of PAR. An 8 hour photoperiod should work fine.


----------



## tusk

Thanks for the advise and the effort you put in this thread!


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## SpankyMR2

Hoppy,

I'm new and I do not completely understand the charts. In advance, let me say that I appreciate all of your work on lighting. I have a 65 gallon tank that is 4x1x2. I have a coral life t5 fixture that has 1 tho 10,000k 54w whtie bulb and 1 tho colormax 54w redish bulb. What would this be considered? If I'm reading your char correctly, I would have a high light tank?

Patti


----------



## Hoppy

SpankyMR2 said:


> Hoppy,
> 
> I'm new and I do not completely understand the charts. In advance, let me say that I appreciate all of your work on lighting. I have a 65 gallon tank that is 4x1x2. I have a coral life t5 fixture that has 1 tho 10,000k 54w whtie bulb and 1 tho colormax 54w redish bulb. What would this be considered? If I'm reading your char correctly, I would have a high light tank?
> 
> Patti


Yes, you almost certainly have high light, but not so high as to be impossible to live with. You do need pressurized CO2, good non-limiting fertilizing, and good water circulation in the tank to avoid algae problems. If that fixture comes with legs, raising it with the legs might lower the light intensity enough to go without CO2.


----------



## JVKos

FWIW, that chart on the first page is rubbish, most likely some propaganda for HQI lighting from the looks of it. There should be different shapes to the curves... linear bulbs dont follow the inverse square law until you reach a distance from the bulb equal to its length. Metal halides, Plasma Vapor (same profile with regards to distance, but higher efficiency than halide; tops out at 150 lm/w), and other point source lights diminish quicker with distance in comparison, with some variation based on the reflector dispersion.


----------



## Hoppy

JVKos said:


> FWIW, that chart on the first page is rubbish, most likely some propaganda for HQI lighting from the looks of it. There should be different shapes to the curves... linear bulbs dont follow the inverse square law until you reach a distance from the bulb equal to its length. Metal halides, Plasma Vapor (same profile with regards to distance, but higher efficiency than halide; tops out at 150 lm/w), and other point source lights diminish quicker with distance in comparison, with some variation based on the reflector dispersion.


No simple chart will ever give you an absolutely accurate estimate of the light from a range of light sources. The chart is one attempt to find a better way to do that than using watts per gallon, which truly is rubbish. I challenge you to work on this problem too, and find a better way to determine the best light source for any size and shape tank. I feel certain it can be done, and will be done by someone. Maybe that will be you?


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## enlender

*Light Question looking at your chart and tables*

Hi im just about to order a new light for my 28g bowfront that sits at 18"tall i have about 2 inches of gravel in parts and close to 5 in another is it safe to assume that a 2bulb t5ho fixture will be highlight at the 2inch substrate mark and too high at the 5? will i have to pump tons of co2 to get this to be ok or should i look into a single MH fixture or t5no bulbs. i do have co2 so that wont be an issue.

Thanks for your input

Evan


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## Hoppy

enlender said:


> Hi im just about to order a new light for my 28g bowfront that sits at 18"tall i have about 2 inches of gravel in parts and close to 5 in another is it safe to assume that a 2bulb t5ho fixture will be highlight at the 2inch substrate mark and too high at the 5? will i have to pump tons of co2 to get this to be ok or should i look into a single MH fixture or t5no bulbs. i do have co2 so that wont be an issue.
> 
> Thanks for your input
> 
> Evan


A two bulb T5HO fixture will be too much light at all levels in the tank, about twice what would be good high light. It isn't possible to get the same light intensity at two different levels in the tank, with one light fixture, so you have to decide which level is the farthest from the bulbs where you will want plants to grow at the rate that you want. Then you pick a light to give you the appropriate intensity at that level, knowing the intensity will be higher up closer to the bulbs, and lower at longer distances from the bulbs. 

With tanks with a large front to back dimension, 18 inches, for example, you can use two different lights over the front and the back of the tank, so that would let you have lower intensity at the back, if you want, and higher at the front.

In my opinion, the best lighting is where there is just enough light intensity at the substrate for low, or just starting to grow plants to grow well. Then those plants will have plenty of light as they get bigger, and the low plants will still be able to grow.


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## bnbfishin

Question for ya Hoppy. What would be better, 1-48" T5HO bulb or a twin tube T5HO 36" striplight on a 55 gallon tank? Mounted into the canopy making the bulbs aprox 3 inches above the top of the tank and the substrate ranging from 2 inches deep to 4 inches deep. Any reason not to do the 36" on a 55? Standard dimensions on the tank 48x12x20

Second part to my question is how do I know which bulbs to use in the fixture I decide on? I see some that are simply labeled as "plant bulbs", full spectrum/sun bulbs, 5000K, 6500K, 6700K, 10,000K and even 12,000K.

If it matters this will be a fish/live plant tank. 
Thanks a bunch!
Bill


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## Hoppy

The reason for using a full length bulb over a tank is to get the most uniform lighting you can over the full length of the tank. That makes the 48 inch bulbs a better choice than 36 inch bulbs. With two T5HO bulbs, of either length, you would need to suspend the fixture about 25 inches from the substrate level to keep from having such high light that algae would be your primary concern, not enjoying the tank.

Use the bulbs that make the tank look like you think it should look. You need to either see a variety of color temperature bulbs on various tanks, or go by what others describe for how they look. Personally, I like the appearance of some 10,000K bulbs, and some 6700K bulbs, but that doesn't mean I wouldn't like the others too.


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## bnbfishin

Thanks for the info. I'll try to find a single bulb T5HO 48" fixture. So far the double bulb fixtures I have found have to have both bulbs on for the fixture to work which sucks because I have found quite a few of them on [Ebay Link Removed] As for the bulbs it looks like I'll be doing a lot of searching on here for info/pics and see what I like. Otherwise I'll just buy one of each and see what looks best and chalk it up to trial and error since there isn't a shop around here that's worth a darn for that type of info.

Thanks again!
Bill


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## JVKos

Hoppy said:


> No simple chart will ever give you an absolutely accurate estimate of the light from a range of light sources. The chart is one attempt to find a better way to do that than using watts per gallon, which truly is rubbish. I challenge you to work on this problem too, and find a better way to determine the best light source for any size and shape tank. I feel certain it can be done, and will be done by someone. Maybe that will be you?


It matters too much on other things though too. The exact reflector geometry and area (lumenarc 3 style reflectors vs. mini-pendants) will vary the dispersion, in general, the larger the reflector, the further it will carry the light (and the less intense it will be closer to the bulb). T5's and other linear bulbs tend to be less intense as well as you get closer to the bulb (not that many plants or corals need or can even withstand levels higher than the 500-600uMol/m2*s of light that T5's generate at the water surface). Their greater dispersion (larger bulb area and reflector area per watt) means that they will penetrate the water better than halides of similar wattage and bulb efficiency. Watt per watt, T5's are much better at making blur spectrums as well compared to halides. A larger dispersion area over the water surface also means less 'shimmer' or 'glitter lines'. This isnt as much of an issue with freshwater as with saltwater though.

There are too many other factors, as well as one big one, to have a 'computation' possible with lighting and tanks. For one, the light's height above the water and positioning will change everything. Second, just like watts per gallon, any generalizations based on volume are also useless... a 40g cube having a different ideal than a 40Long or a 40Breeder. Third, the glass itself acts as a reflector, and your abilty to keep it clean or let the algae and scum grow over it (even if not algae, the biofilm that forms will change the refraction) will change how much light is kept in the tank or let out, as well as the angles. The contents of the tank will also change the light field... an open tank will have more light at the sand than one with a rock wall in the back. And lastly, there is the water clarity. With the reef, even in a perfect system of waste removal (live rock, zeolith, and denitrification reactors) and carbon for a tested nitrate level of 0, there are still organics in the water that tint it. Versus a 100% fresh fill, the light at the sand after a few months can easily be cut down by as much as 20% (from my own PAR meter readings). White sand, black sand... it all has an impact. Everything in the tank environment is a potential light reflector or absorber.

The other curveball is the LED. As of last year, making a new lighting system with LED's dropped below that of halide or T5 as far as initial cost, and outputs starting with the Cree XP-G series allowed for 1/2 or less the wattage to generate the same amount of light as halide or T5. Considering the long term savings of no bulbs to replace every year, and its no wonder that 2010 is the year where LED's have boomed. From the cost perspective, T5's and halides are obsolete. T5's maybe in actinic or blue for supplimenting LED's (more a saltwater concern than freshwater), but for the most part, it makes no sense to buy anything other than LED's. LED's can be clustered together, spread across a large heatsink, or along a strip... so the light field possibilities are endless.

One thing to consider is something I advocated when I was big-cheese in the reefing community was to buy a PAR meter and do your own light field measurements. Maybe it cant be justified for planted tanks so much, as the inhabitants tend to be a fraction of the cost, and the water tests aren't quite so elaborate, but even if just the local club has a meter that they can loan out, its a big help and the understanding you will gain about your tank's lighting is well worth it. For reefing, its not uncommon to have $300+ in water test kits, a CO2 controller/meter, ORP meter/controller, and lots of money tied up in livestock as well as equipment. Really, whats another $300 for a Quantum meter then? After the clubs started getting the meters, people quit using the relative terms of 'high light' and 'low light' and started using '200-250 uMols/m2*s' instead, as one person's low light is another person's high. Knowing what light levels your plants prefer and maybe even what they are used to in the wild can go a long way then and IMO is way more important and useful than anything else. If I could find existing PAR/PPFD light readings on the various plant species, I would be golden in determining lighting for my new planted tank. I fell like Im running blind otherwise.


----------



## Hoppy

JVKoss I'm assuming then, that you don't believe anyone should even begin a planted tank before doing a lot of trial and error experimenting with various lights to determine, with a PAR meter, which combinations produce the ideal PAR that your particular selection of plants needs. If so, doesn't that kind of kill this as a hobby?

I still believe that people are going to buy a light fixture for their tank, without doing that preliminary research, so they need some way to decide which light to buy, with the bast chance that it will work well for what they want the tank to do. That way cannot be watts per gallon, so something else is needed. My charts are something else, something that works far better than watts per gallon. I'm not nearly vain enough to tell people that a certain light fixture will give them 48 micromols of PAR. I am vain enough to suggest that it will probably give them low to low medium light, and if they look at the charts they can see that I mean about 30 to about 60 micromols of PAR at the substrate level. Plus, by now most of us probably know that low light tanks don't need CO2, high light tanks do need CO2, and medium light tanks will work a lot better with CO2.


----------



## JVKos

Hoppy said:


> The reason for using a full length bulb over a tank is to get the most uniform lighting you can over the full length of the tank. That makes the 48 inch bulbs a better choice than 36 inch bulbs. With two T5HO bulbs, of either length, you would need to suspend the fixture about 25 inches from the substrate level to keep from having such high light that algae would be your primary concern, not enjoying the tank.
> 
> Use the bulbs that make the tank look like you think it should look. You need to either see a variety of color temperature bulbs on various tanks, or go by what others describe for how they look. Personally, I like the appearance of some 10,000K bulbs, and some 6700K bulbs, but that doesn't mean I wouldn't like the others too.


Assuming reflectors are the same on both, the 36" option would shine less light on the glass (at least the ends), so less algae would form. Considering a 3' T5 fixture leaves 6" at the ends, its not a huge deal... if it were lit with pendants like halides, a common rule is one bulb for every 2' of length, so a 4-6" long bulb about 12" from either end, maybe with the reflector you get close to 6" from the end. Some mount their halides up higher because of this (12"), but many do not (5-8") because unless the tank is at least 24" front-to-back, the light spilling out the front is a blinding waste. T5's tend to have shallower reflectors and tend to spill out light across a wider angle, so mounting them high would produce extra glare. If you keep them close to the water, no problem, but if you have to raise the T5's up for dispersion reasons, I wouldnt bother because of the glare (unless you have a canopy). I like the effect of having darker areas in the corners and ends... so I would leave the side top corners dark. The light will spread out on its own within 6", of depth, so not having a full length bulb isn't a big deal unless you plan on having long blades of val/sag coming up from the ends.

OTOH, a single 48" bulb will have a more even light field with regards to not only side-to-side, but height as well. Its greater length will allow it to penetrate deeper in the water. Maybe you want this... maybe you dont...


----------



## JVKos

Hoppy said:


> JVKoss I'm assuming then, that you don't believe anyone should even begin a planted tank before doing a lot of trial and error experimenting with various lights to determine, with a PAR meter, which combinations produce the ideal PAR that your particular selection of plants needs. If so, doesn't that kind of kill this as a hobby?
> 
> I still believe that people are going to buy a light fixture for their tank, without doing that preliminary research, so they need some way to decide which light to buy, with the bast chance that it will work well for what they want the tank to do. That way cannot be watts per gallon, so something else is needed. My charts are something else, something that works far better than watts per gallon. I'm not nearly vain enough to tell people that a certain light fixture will give them 48 micromols of PAR. I am vain enough to suggest that it will probably give them low to low medium light, and if they look at the charts they can see that I mean about 30 to about 60 micromols of PAR at the substrate level. Plus, by now most of us probably know that low light tanks don't need CO2, high light tanks do need CO2, and medium light tanks will work a lot better with CO2.


No, I think there are certain 'cookie cutter' lighting arrangements for any given tank depending on what you wish to keep. Most tanks tend to be pre-built and so a listing of 'ideals' based on these sizes is the easiest. If you have something else that is DIY or unusual, you can at least ballpark what you should use based on the closest thing on a 'cookie cutter' list. From there, then yes, you can use a light meter (PAR is ideal, but even a less expensive lux meter will work for similar spectrums: it seems like freshwater tanks have a narrower spectrum of desirable bulb color). The light meter allows the 'seller' of the main colony to take readings of the light where the plant is growing, and then the 'buyer' can use that number to find where in their tank those levels exist if available. I know plants can adapt somewhat, and they will grow over time, but that way we do have a benchmark standard. In 'reefing' now, its common to see composite photos of people's aquariums with the light levels written where each coral is, the sand is, the corners, middle, and water surface. Most people dont even need a meter to guess what their light levels are like; they can simply reference someone else's aquarium from the diverse library of composites who happens to have similar lighting levels and the work has been done for them.

I would like to measure some planted tanks though to see what the measured levels are and get some numbers to go by. 30-60umols' is helpful (thank you) but far from the whole story. Knowing if this is for a low or high intensity tank, the intensity at the surface and the distance between would really fill me in. Then I can make my LED array(s) to match it. Based on that sort of info, I could compute the ideal lighting setup for any size aquarium and put it into a spreadsheet with estimated lighting zones.

Still, even with a lumens/gallon or PAR/gallon figure, the shape of the tank will vary the exact need (tall tends to need more than short and wide), and so will my intended light area. Maybe I want to only 'spotlight' a central area and leave the rest darker... in which case alot less is needed.


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## Hoppy

May I suggest that you watch this forum for when people ask what light fixture or what type of fixture or which of two fixtures will work for what they want it to do. Then offer your suggestions for those specific circumstances. The more good suggestions people get, the easier it is to make good decisions. We have lots of room here for different opinions.


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## NJAquaBarren

I was thinking that the industry needs a standard metric. PAR is the base, but a standard for comparion using STD, common tank dimensions for comparison.

LEDs are obviously highly variable, but even the light from my 2 2-bulb T5-HO fixtures is very different due to the reflectors.

So how about Something like a PAR value at 24 inches. Should be possible to calculate change with height deltas, but would it help we had that one number for all light fixtures?


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## JVKos

One number is not really possible, since the light field at any point consists of magnitude and direction, and across an area, this turns into intensity and spread. If you have ten 60 watt tungsten bulbs in one room vs. one in each of ten rooms of the house, which is brighter? Thats why any quantitative light measurements are done on a grid (Dr. Sanjay Joshi's work is a perfect example.


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## Register

Hoppy, been reading this thread and I am rethinking my lighting plans.

I have two tank set up

5.5 gal.
I am looking at building a light for my 5.5 gal tank and was looking at the AH supply Kits. What kit would be my best option for low/medium light tank, 18w or 24w? Would I be better off getting two 13w kits and running them end to end? Hoping to find a happy medium of lighting that will be enough and run the length of the tank and not too much light.

20 gal. long
Would the AH 24W kit be enough for the same set low/medium light setup or should I step up to the 36W kit? 

Or would I be better off sticking with standard florescent for both tanks? Like using less power as possible

Thanks!


----------



## Hoppy

Register said:


> Hoppy, been reading this thread and I am rethinking my lighting plans.
> 
> I have two tank set up
> 
> 5.5 gal.
> I am looking at building a light for my 5.5 gal tank and was looking at the AH supply Kits. What kit would be my best option for low/medium light tank, 18w or 24w? Would I be better off getting two 13w kits and running them end to end? Hoping to find a happy medium of lighting that will be enough and run the length of the tank and not too much light.
> 
> 20 gal. long
> Would the AH 24W kit be enough for the same set low/medium light setup or should I step up to the 36W kit?
> 
> Or would I be better off sticking with standard florescent for both tanks? Like using less power as possible
> 
> Thanks!


You need to start with the height of the tank, before you can evaluate any lighting. The farther the substrate is from the light the brighter the light ha to be to have enough light down there to get plants started growing, and keep the bottom leaves healthy. Once you know the tank height, you can assume any light sitting on top of the tank will have the bulb(s) about as far above the top of the tank as the substrate is thick - crude, but a starting point. Then, every type of lighting has its own basic brightness, whether T12, T8, T5NO, T5HO, or PC. So, that tank height tells you about what type of light you need. If you are willing and able to suspend the light above the tank, you can use just about any type of light, as long as it is bright enough, so that lets you use MH lights also.


----------



## scapegoat

so this is slightly confusing. basing the height and type of light to decide low/med/high seems to elude to the fact that you can use a 55w AHS PC or a 96W AHS PC with no difference if the height is the same from the substrate.

or are we to assume that your chart dictates the same wattage across test subjects?

I'm sure these things are answered throughout this thread... but at 20 posts shy of 300, i can't read through them all.

i guess what i'm really asking is... how are we to decide, based on your chart, what specific bulb of the chosen type we should purchase? ie: 55w or 96w from AHS


----------



## HolyAngel

scapegoatw said:


> so this is slightly confusing. basing the height and type of light to decide low/med/high seems to elude to the fact that you can use a 55w AHS PC or a 96W AHS PC with no difference if the height is the same from the substrate.
> 
> or are we to assume that your chart dictates the same wattage across test subjects?
> 
> I'm sure these things are answered throughout this thread... but at 20 posts shy of 300, i can't read through them all.
> 
> i guess what i'm really asking is... how are we to decide, based on your chart, what specific bulb of the chosen type we should purchase? ie: 55w or 96w from AHS


Reflector matters a LOT too, the T5HO reference line in the chart is based off a Tek fixture with an individual reflector for that one bulb, which if it works as advertised, means the brightness is increased 3-fold, without it, I bet it wouldn't be much brighter than the T5NO.. 

And the chart wouldn't be applicable for say an odyssea or coralife fixture that has a single reflector for both/all 4 lights as opposed to individual reflectors.. 

Nor does it really take into account spread..

If you have a Tek or icecap light system with those reflectors, the chart will hold true all day.. But a t8 with those reflectors do not. +what you said. The chart is just a guideline. If you want to know for sure, you'll have to either get your hands on a PAR meter or look at what other people are doing and try to replicate it or extrapolate what will work for you..


----------



## Hoppy

scapegoatw said:


> so this is slightly confusing. basing the height and type of light to decide low/med/high seems to elude to the fact that you can use a 55w AHS PC or a 96W AHS PC with no difference if the height is the same from the substrate.
> 
> or are we to assume that your chart dictates the same wattage across test subjects?
> 
> I'm sure these things are answered throughout this thread... but at 20 posts shy of 300, i can't read through them all.
> 
> i guess what i'm really asking is... how are we to decide, based on your chart, what specific bulb of the chosen type we should purchase? ie: 55w or 96w from AHS


The difference between a 55 watt and a 96 watt PC light of the type we use on aquariums is just the length. If a 55 watt bulb is close to the length of the tank, use it. If the tank is much longer than a 55 watt bulb, use a 96 watt bulb. If the tank is still longer, use whatever combination of lengths of bulbs will span the length of the tank. Remember, all a light can do is light up the area beneath it. It does not magically mix light with the water to spread it uniformly over the whole tank. And the further you are away from directly under the bulb, the less the light intensity.

Wattage is not a measure of light. Wattage is just the amount of electricity needed to light up the bulb.

Don't make the mistake of believing there is any precision in selecting a light for an aquarium. There isn't. You just pick the light that is most likely to give you the light intensity you want. Then, if you want more precision you need to get a PAR meter and start measuring, and adjusting the height of the light, and/or the spacing between lights above the tank.

Your other choice is to adopt an absurd standard that presumes that watts are something a light pours into the water to give you an amount of light that is proportional to the volume of the tank. Then you buy a light based on that, and suffer either continual algae woes or inability to grow plants because of too little light.

This is a better way to choose a light, not a perfect way.


----------



## scapegoat

that explains a lot thank you. I was really under the assumption that the watts had something to do with how much light is being given off... but thats not the case. i will forget i ever thought that now.


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## angelicodin

Just wanted to say thanks to hoppy and everyone else who has contributed on this thread, it really helped my out when I was first learning about all of this. Vary easy to read and understand to help me with choosing the right lighting setup for my tank.


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## JRunyon21

I have two lighting questions. I have been planning on a 250g tank and was thinking of going planted. I have most of the equipment already and one thing I have is a T5HO ballast. The ballast holds UP TO 4 T5HO 54W bulbs. These bulbs are 46" in length and my tank is going to be approx 85" in length. This means that altho I have 4 bulbs, I will essentially have 2 T5HO bulbs running the length of my tank. After planning the the canopy, the lights should sit 3' above the substrate. 

Sooooooooo....

First question.
Will 2 T5HO bulbs, running the length of the 250g aquarium, 3' above the substrate, be enough light to have a low-med light planted tank? lololol.

Second question
I am currently trying to grow plants in a 5g(Need somethin to hold me over til I get my 250g). Is a 8W T5NO bulb, running the length of a 5g, 12" above the substrate, enought light for a low-med planted tank?


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## jakera

Hi Hoppy. May I ask you a question.

But first, let me say that this is just an amazing find. The only problem is that my english is not that good to understand your chart fully.
I have an Akvastabil aquarium which is 140gallons. The height is 23,6 inches and my substrate is about 3,5 inch. But the hood is a bit curved, so the bulbs are a bit higher( what i mean by that is that they are not sitting on the top). So I would assume them to be from the top of glass, like 2,7 inches. To sum it up, the height between substrate and bulbs would be around 22,8 inches. 
Right now I have 2x54w T5HO bulbs. Do I read the chart correctly that I have low light?
Which means, that in order to get high light, I would have to add two bulbs more, for total of 4x54w?
Correct me if I am wrong.

Do hope you can help me Hoppy:/


----------



## Hoppy

One T5HO bulb, 23 inches from the substrate should give you about 50 micromols per meter squared per second of PAR, so two bulbs, close together, should give you about 100 micromols of PAR. That is high light.

If the two bulbs are about 8 or more inches apart, they should give you just a little more than 50 micromols of PAR, which is low-medium light. I assume your tank is about 28 inches from front to back. If that is true, it will be hard to get uniform light with two bulbs. It would be much better, if you want high light, to use 2 lights, each with 2 T5HO bulbs, with one light near the front of the tank and one near the back of the tank. Or, for low-medium light, you can use just two bulbs, one near the front of the tank and one near the back of the tank.


----------



## Lipticlear

Hi hoppy, thanks so much for the awesome post! I have been reading through for about an hour now and I haven't found my specific question. I am looking to get to the highest light level where I will not need to supplement with co2 to start. If I am at a high non co2 level, once I do decide to give co2 a try, it will just make everything grow that much faster. I don't want to have an algae issue either. 

So my set up is a 33 gallon 18 inches deep, with a glass lid. Substrate is about 3". I will either mount the light right on the top, or use the supplied mounts which would raise the light up a couple inches dependant upon the model that I get. I am thinking a T5 HO single strip light (36" long which is the length of my tank) would be the way to go. Would this get me to a level where I would not need co2? Or would this still be too much light? Hanging the light to allow for further spread may not be a option as I have ductwork where I would have to hang the light from. Thoughts on what I should go with? 

Cheers.


----------



## jakera

Hoppy said:


> One T5HO bulb, 23 inches from the substrate should give you about 50 micromols per meter squared per second of PAR, so two bulbs, close together, should give you about 100 micromols of PAR. That is high light.
> 
> If the two bulbs are about 8 or more inches apart, they should give you just a little more than 50 micromols of PAR, which is low-medium light. I assume your tank is about 28 inches from front to back. If that is true, it will be hard to get uniform light with two bulbs. It would be much better, if you want high light, to use 2 lights, each with 2 T5HO bulbs, with one light near the front of the tank and one near the back of the tank. Or, for low-medium light, you can use just two bulbs, one near the front of the tank and one near the back of the tank.


Thank you for your reply Hoppy.
My tank is 21inches from front to back and the lenght is 63 inches.
What would happen if I use 4 T5HO bulbs evenly distributed under the hood and for example use the first and fourth bulb for half the time and the second and third bulb for the other half of the time? Would that give me medium light?


----------



## Hoppy

jakera said:


> Thank you for your reply Hoppy.
> My tank is 21inches from front to back and the lenght is 63 inches.
> What would happen if I use 4 T5HO bulbs evenly distributed under the hood and for example use the first and fourth bulb for half the time and the second and third bulb for the other half of the time? Would that give me medium light?


It depends on how high the hood is - how far it holds the lights above the substrate. If it puts the bulbs near the top of the tank I think you would get medium light operating it that way. But, 48 inch (actually closer to 46 inch) long bulbs aren't going to light the ends of a 63 inch long tank very well.


----------



## Hoppy

Lipticlear said:


> Hi hoppy, thanks so much for the awesome post! I have been reading through for about an hour now and I haven't found my specific question. I am looking to get to the highest light level where I will not need to supplement with co2 to start. If I am at a high non co2 level, once I do decide to give co2 a try, it will just make everything grow that much faster. I don't want to have an algae issue either.
> 
> So my set up is a 33 gallon 18 inches deep, with a glass lid. Substrate is about 3". I will either mount the light right on the top, or use the supplied mounts which would raise the light up a couple inches dependant upon the model that I get. I am thinking a T5 HO single strip light (36" long which is the length of my tank) would be the way to go. Would this get me to a level where I would not need co2? Or would this still be too much light? Hanging the light to allow for further spread may not be a option as I have ductwork where I would have to hang the light from. Thoughts on what I should go with?
> 
> Cheers.


With high light good CO2 is a must. With medium light, you might get by without CO2. With low medium or low light you can get by without CO2.

If you have a single T5HO bulb 15 inches from the substrate you will need good CO2. At 18 inches I doubt that you could avoid algae problems without CO2. At 20 inches you can probably do OK without CO2. At 24 inches you should be able to do without CO2. You can add a layer of fiberglass window screen (insect screen) between the light and the plants, reducing the intensity by 40%. If you did that, at 15 inches you would have medium light with the one T5HO bulb, or low medium with the bulb 18 inches from the substrate. Remember, CO2 helps the plants grow even at low light, so it is never a bad idea to have CO2.


----------



## Lipticlear

Ok so it sounds like the single is the way to go then. Thanks for the confirmation. I will have to see if I can DIY some kind of support so that I can suspend the light. Hanging from the ceiling is not really an option. Thanks again for all the time you put in here. It gets all of us newbies off on the right foot!!! Cheers!!!


----------



## tharsis

Hi Hoppy,

Have you or anyone that you are aware of tried to quantify the effect of a good (individual reflector per bulb) vs poor reflector (single reflector for all bulbs)? I tried to search for an answer but was unsuccessful.

Do you have an estimate on the % decrease in PAR between the two? I realize there are alot of variables but would it be on the order of a 10% decrease or closer to %30 and above? 

The reason I ask is that I was looking at getting the odyssea T5HO 2 bulb fixture for my 75 gallon tank and I want to be in the high light range. 

It will be sitting on the tank (with the legs) so I figure ~21" above the substrate. With a TEK fixture that would put me well into the high light range with 60 micromols x 2, but anything greater than a %30 decrease in efficiency will put me into the medium light zone. 

What do you think?

Thanks!


----------



## tom855

Lipticlear,

I just finished making a DIY hanging kit that holds up my 36" fixture about 14" over the top of the tank. I'd guess it cost me about $20 total for EVERYTHING needed to do it, including a can of black spray paint. If you are interested I can post a few pictures and simple instructions. Neglecting my ADHD it probably took less than 3 hours total.

I wish I had done it a long time ago. FINALLY I can measure and adjust my light level on the substrate.

Tom 

.


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## Hoppy

Recently I tested a screw-in CFL light with and without a simple two bend aluminum reflector, not very highly polished. The reflector doubled the PAR readings. That's the only test I have done.

This isn't rocket science. If you can look up at the bulb and reflector, and see two more bulbs, one on each side of the real bulb, you approximately double the amount of light you get. If you can see even more bulbs on each side of the real bulb, you more than double the amount of light. (Do this with the light off, not on.) All that a simple reflector does is capture the light from the sides of the bulb not facing the aquarium and redirect it to the aquarium. A curved or parabolic reflector is harder to "test" this way, since you see something other than extra bulbs when you do this. But most aquarium light reflectors are simple multiple bend flat reflectors. See the AH Supply illustration, http://www.ahsupply.com/36-55w.htm for what I mean about multiple bends. Some websites claim a tripling of the light from the bulbs using their reflectors.


----------



## Hoppy

tom855 said:


> Lipticlear,
> 
> I just finished making a DIY hanging kit that holds up my 36" fixture about 14" over the top of the tank. I'd guess it cost me about $20 total for EVERYTHING needed to do it, including a can of black spray paint. If you are interested I can post a few pictures and simple instructions. Neglecting my ADHD it probably took less than 3 hours total.
> 
> I wish I had done it a long time ago. FINALLY I can measure and adjust my light level on the substrate.
> 
> Tom
> 
> .


A post, with photos, on the DIY forum would be very useful to a lot of people.


----------



## Loop

Just to make sure I'm using your graph right:

T5HO fixture with two bulbs. On legs attached to a 29 Gallon tank. Light sits 18" from substrate.

T5HO at 18" = PAR of 80

PAR 80 x 2 bulbs = PAR 160 (AKA : ridiculously bright) 

If that's right, I should use just one bulb or raise the light to 25" to get Medium High light. 

I think I'm reading this right but wanted to double check because when I turn off one bulb the tank appears very dim. I know that my perception of light isn't the same necessarily as what the plants are receiving, but I don't think it really looks good that dim either. I'm assuming I'll just have to come up with a way to hang it.


----------



## Hoppy

Loop said:


> Just to make sure I'm using your graph right:
> 
> T5HO fixture with two bulbs. On legs attached to a 29 Gallon tank. Light sits 18" from substrate.
> 
> T5HO at 18" = PAR of 80
> 
> PAR 80 x 2 bulbs = PAR 160 (AKA : ridiculously bright)
> 
> If that's right, I should use just one bulb or raise the light to 25" to get Medium High light.
> 
> I think I'm reading this right but wanted to double check because when I turn off one bulb the tank appears very dim. I know that my perception of light isn't the same necessarily as what the plants are receiving, but I don't think it really looks good that dim either. I'm assuming I'll just have to come up with a way to hang it.


You are reading it correctly. One reason it looks dim with only one bulb is that we get used to what we see. If we see a very high light tank for a few days, that seems to be just ordinary light. Then, when we reduce it by half or more, it looks too dim to ever work. What do you think the planted tankers would have thought 10 years ago if we had told them that they would soon be worried more about having too much light than about not having enough? Back then "too much" was never used in a conversation about light.


----------



## Loop

Thanks alot Hoppy. For the help and all the info, research, and testing you provide. I couldn't even count all the times I've read some write-up or something, that you took the time to do, when I'm looking for answers. I know everyone else here appreciates it just as much as I do.

Next time I'm in CA I'm buying you a drink.



EDIT: Wait, I just thought of something else. I think I remember reading somwhere that you can use T5NO bulbs in a T5HO fixture and that the bulbs will operate the same as they normally would in a T5NO fixture. I might be wrong but I think I read that before. If that's true and I refer to a discussion on the first page of this thread saying that T5NO lights put out slightly above 1/2 the light of T5HO lights, just swapping my bulbs should give me a more reasonable light range. Taking my last calculation of PAR 160 down to around abou 85-90 approximately. Maybe?


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## StillLearning

Hoppy I have a question for you I have a 55 gallon with glass tops on them. I have a 4 x 54 Catalina Aquarium fixture with two giesemann aqua flora and two giesemann midday bulbs in them. How high would you recommend it from the substrate with the glass tops on it and how high would you recommend it without the tops on? Thanks again.


----------



## Hoppy

Loop said:


> Thanks alot Hoppy. For the help and all the info, research, and testing you provide. I couldn't even count all the times I've read some write-up or something, that you took the time to do, when I'm looking for answers. I know everyone else here appreciates it just as much as I do.
> 
> Next time I'm in CA I'm buying you a drink.
> 
> 
> 
> EDIT: Wait, I just thought of something else. I think I remember reading somwhere that you can use T5NO bulbs in a T5HO fixture and that the bulbs will operate the same as they normally would in a T5NO fixture. I might be wrong but I think I read that before. If that's true and I refer to a discussion on the first page of this thread saying that T5NO lights put out slightly above 1/2 the light of T5HO lights, just swapping my bulbs should give me a more reasonable light range. Taking my last calculation of PAR 160 down to around abou 85-90 approximately. Maybe?


One member here tested some T5NO and HO bulbs in a HO fixture, and found, for that fixture, the NO bulbs were operating as NO and not HO. I don't know if that will be universally true or not, nor do I know if the NO bulbs were being slightly overdriven, but not enough for the measurements he took to pick it up. I don't have a T5 fixture, so I haven't tried it.


----------



## Hoppy

StillLearning said:


> Hoppy I have a question for you I have a 55 gallon with glass tops on them. I have a 4 x 54 Catalina Aquarium fixture with two giesemann aqua flora and two giesemann midday bulbs in them. How high would you recommend it from the substrate with the glass tops on it and how high would you recommend it without the tops on? Thanks again.


I have never tested the effect of a glass top on the PAR a light will give. From what I know about light I don't think a clean glass top would have much effect on the PAR.

If you want high light, you could try raising the 4 bulb light about 10 inches above the top of the tank.


----------



## Capncrunch7

Apologies if I'm mistaken, but I haven't seen any information pertaining to shallow tanks. I have a standard 2.5g that is 8 inches tall. 

This is the light fixture I use (with 2x 6W 10k bulbs):
http://coralifeproducts.com/product/hoods-light-fixtures/#mini

If it is directly on top of the tank, what sort of lighting does that produce?


----------



## StillLearning

Hoppy said:


> I have never tested the effect of a glass top on the PAR a light will give. From what I know about light I don't think a clean glass top would have much effect on the PAR.
> 
> If you want high light, you could try raising the 4 bulb light about 10 inches above the top of the tank.


Thank you I will try that and see how things go. Thanks again.


----------



## tom855

Capncrunch7 said:


> Apologies if I'm mistaken, but I haven't seen any information pertaining to shallow tanks. I have a standard 2.5g that is 8 inches tall.
> 
> This is the light fixture I use (with 2x 6W 10k bulbs):
> http://coralifeproducts.com/product/hoods-light-fixtures/#mini
> 
> If it is directly on top of the tank, what sort of lighting does that produce?



I can't answer your question exactly, but I just measured my 13W Ottlight about 8" over the substrate in my 2.5g. It's ~50um. If I raise the light another 2" or so it drops to 30um. 

All that said, your results depend a lot on the reflector you have. I can tell you what I'm seeing but as they say, your mileage will vary.

Hope that help!

Tom


----------



## Seattle_Aquarist

Hi Hoppy,



Hoppy said:


> I have never tested the effect of a glass top on the PAR a light will give. From what I know about light I don't think a clean glass top would have much effect on the PAR.


I responded to a similar question on another forum in this thread. The results were interesting. It was a standard 30 gallon (36" length) with an 2X36 watt (6700K) AH Supply kit over a Aqueon Versa-Top. With new bulbs and no glass top the PAR = 110; with "dirty"* Versa-Top in place PAR = 96; with cleaned Versa-Top in place PAR = 101. All readings were taken with new bulbs @ substrate level about 13 inches below the fixture.

*dirty = lots of dried water spots on top, condensation; dust


----------



## Hoppy

Seattle_Aquarist said:


> Hi Hoppy,
> 
> 
> 
> I responded to a similar question on another forum in this thread. The results were interesting. It was a standard 30 gallon (36" length) with an 2X36 watt (6700K) AH Supply kit over a Aqueon Versa-Top. With new bulbs and no glass top the PAR = 110; with "dirty"* Versa-Top in place PAR = 96; with cleaned Versa-Top in place PAR = 101. All readings were taken with new bulbs @ substrate level about 13 inches below the fixture.
> 
> *dirty = lots of dried water spots on top, condensation; dust


Very good! Thank you. So, we can assume that a glass top on the tank will drop the PAR by about 10% - less than the uncertainty in what PAR you should get without the glass, so it can be ignored. And, a dirty glass can reduce it by about another 5%, again less than the uncertainty, so can be ignored. Since the charts also do not account for the small increase in PAR caused by the air to water interface, and reflection off the glass, the glass top probably has no more than the same effect, but in the opposite direction, as putting water in the tank. Before we can get serious about any of those effects we would need much more accurate charts.


----------



## Jeffww

My fixture has mirror reflectors. Have you done any tests on the effects of mirror reflectors as opposed to white backings?


----------



## Delgriffth

this thread has helped me solve my algae problems in my 40g breeder. i also have a 20g tall with t5 fixture sitting on top of the tank. both the 40g breeder and 20g tall are 16" high. with 2 bulbs over each tank. 20g tall 48w and 40g breeder 78w. i never measured the tanks with a par meter. i used ei dosing, pressurized co2 and tap water on both tanks. the 20g had no problems with algae the 40g had terrible bouts with diatom etc. even though the 20g had more wpg the 40g had the problems. the 20g had 24w bulbs 16" from substrate and the 40g had 39w 16" from substrate. obviously a 39w was much more intense then the 24w at the same 16". once i moved the 40g fixture up off the tank the algae problems went away. great thread.


----------



## Hoppy

Jeffww said:


> My fixture has mirror reflectors. Have you done any tests on the effects of mirror reflectors as opposed to white backings?


If, by "mirror" reflectors, you mean glass mirrors, those are inferior light reflectors compared even to white paint. But, if you mean the highly polished aluminum reflectors made of MIRO 4 or equivalent, those are typical for T5HO lights, AH Supply lights, and a few others. They are the best light reflectors we can get. But, I found that a sheet of thin aluminum, not well polished, would double the PAR I could get from a simple screw-in CFL bulb. Aluminum in any form reflects light very well, and reflects the complete spectrum of visible light equally well.


----------



## farmhand

Delgriffth said:


> this thread has helped me solve my algae problems in my 40g breeder. i also have a 20g tall with t5 fixture sitting on top of the tank. both the 40g breeder and 20g tall are 16" high. with 2 bulbs over each tank. 20g tall 48w and 40g breeder 78w. i never measured the tanks with a par meter. i used ei dosing, pressurized co2 and tap water on both tanks. the 20g had no problems with algae the 40g had terrible bouts with diatom etc. even though the 20g had more wpg the 40g had the problems. the 20g had 24w bulbs 16" from substrate and the 40g had 39w 16" from substrate. obviously a 39w was much more intense then the 24w at the same 16". once i moved the 40g fixture up off the tank the algae problems went away. great thread.


Were the T5's above the 20 Tall T5NO or T5HO?


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## Delgriffth

t5ho


----------



## LesPaul

thats what i understand from what i read on this forum and light research on internet
-our regular lightmeters measures (whatever its called luxmeter ,lumenmeter etc) how bright a light is to the human eye which is mostly in the green wavelength
-a parmeter measures or counts actual photons that hit the sensor in the whole visible spectrum
-my cocnlusion is an incandescent ,a halogen bulb or a plantgrow bulb would give us the same par reading from different distances that means we need a parmeter to figure out how many bulbs we need and/or how high we shoul hang them.we still need to know the spectral distribution when choosing a bulb for our planted tanks.

did i understand it correctly?


----------



## Hoppy

LesPaul said:


> thats what i understand from what i read on this forum and light research on internet
> -our regular lightmeters measures (whatever its called luxmeter ,lumenmeter etc) how bright a light is to the human eye which is mostly in the green wavelength
> -a parmeter measures or counts actual photons that hit the sensor in the whole visible spectrum
> -my cocnlusion is an incandescent ,a halogen bulb or a plantgrow bulb would give us the same par reading from different distances that means we need a parmeter to figure out how many bulbs we need and/or how high we shoul hang them.we still need to know the spectral distribution when choosing a bulb for our planted tanks.
> 
> did i understand it correctly?


No, you didn't understand it completely correctly. A PAR meter and a Luxmeter can be the same device, but with different filters, lenses, and calibrations. Both applications are a measure of the photons that pass through a unit area.

Light intensity from any relatively small source decreases with the square of the distance from the source. We can use that, plus 2 or 3 PAR or Lux readings at different distances to determine the intensity at any distance, which is what I did for those charts. Because the intensity drops with distance we have to pick a "standard" location in aquariums to measure the light intensity, knowing that higher or lower in the tank the intensity is higher or lower. I picked the substrate level because if we have enough light there, we certainly have enough everywhere else in the tank. The distance from the bulb affects the intensity the same whether the light passes through air or water, with secondary effects from the air-water interface and from reflections off the glass.

Spectrum is important, but is secondary to the PAR reading. All fluorescent bulbs that produce light that seems pretty white to us will grow plants well.


----------



## Jeffww

Hoppy said:


> If, by "mirror" reflectors, you mean glass mirrors, those are inferior light reflectors compared even to white paint. But, if you mean the highly polished aluminum reflectors made of MIRO 4 or equivalent, those are typical for T5HO lights, AH Supply lights, and a few others. They are the best light reflectors we can get. But, I found that a sheet of thin aluminum, not well polished, would double the PAR I could get from a simple screw-in CFL bulb. Aluminum in any form reflects light very well, and reflects the complete spectrum of visible light equally well.



They are MIRO 4 polished aluminum reflectors. So would that mean: 

on a 12" tall tank with 2xT5HO I would probably need to remove one bulb or suspend it 24" + away from the tank's surface for high light?


----------



## Hoppy

Jeffww said:


> They are MIRO 4 polished aluminum reflectors. So would that mean:
> 
> on a 12" tall tank with 2xT5HO I would probably need to remove one bulb or suspend it 24" + away from the tank's surface for high light?


It would need to be about 20-24 inches from the substrate, not from the top of the tank, to get high light A single bulb would need to be about 15-18 inches from the substrate to get high light.


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## Seattle_Aquarist

Hi Hoppy,

I do have one question; how did you determine the PAR reading ranges for the Low, Medium, and High light catagories? IE 25 - 45 PAR = Low Light; 45 - 80 PAR = Medium Light Is this information available somewhere?


----------



## Hoppy

Seattle_Aquarist said:


> Hi Hoppy,
> 
> I do have one question; how did you determine the PAR reading ranges for the Low, Medium, and High light catagories? IE 25 - 45 PAR = Low Light; 45 - 80 PAR = Medium Light Is this information available somewhere?


I'm not aware of anyone actually doing the research to determine what PAR levels, at the substrate, are logically "low", "medium", or "high" light. It isn't even something that has been defined carefully - what does "low" mean, etc. So, when I started working with PAR, PAR meters, and miscellaneous PAR data, I asked Tom Barr what PAR levels would best correspond to what we call low, medium and high light. The levels he recommended are what I use. But, I use them differently from what I think he intended, and certainly differently from what reef tank keepers do.

To make lighting decisions accessible to everyone you need a simple criteria for what constitutes high, low, etc light. I chose to use the PAR at the substrate, figuring that all plants start their lives there, so that is where you need some minimum amount of light before they can do so.

This is only a start on finding a good way to determine appropriate lighting for a planted tank, one that I think is infinitely better than just using "watts per gallon", but which is still very crude, and will continue to be until someone finds a better way. The only alternative I see now is for someone to be the "expert" who is consulted for everyone's situation and recommends a specific light fixture, made by a specific manufacturer, and located at some specific point above that tank. That would be a terrible solution, in my opinion.

Clearly it is better to actually use a PAR meter on your own tank and make your judgment about that light based on what PAR readings you get. But, to do that you have to first buy what may well be an inappropriate light and try it before you can do the measuring. And, you still need to know where in the tank to take the measurements, and what they mean, both of which are not self evident.

In nature, in shallow waters, the PAR from the sun is the same everywhere that isn't shaded, the same at the surface as at the substrate. But, because our lights are not 90 million miles above the tank, but perhaps only 12 inches, we can't hope to duplicate that. This makes it much more complicated. I hope someone has an inspiration and finds a much better way to do this than I found.


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## Seattle_Aquarist

Hi Hoppy,

GSAS is doing our Home Show this weekend where "judges" visit member homes. We take pictures and do a short video of each tank with member comments as dialog. This year I am taking the club's PAR meter with us and will be doing some readings of member tanks.

So the data I acquire may be of some relevance to what you have done; along with reading at the substrate level at what other level(s) (depths) did you take readings?


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## Hoppy

Seattle_Aquarist said:


> Hi Hoppy,
> 
> GSAS is doing our Home Show this weekend where "judges" visit member homes. We take pictures and do a short video of each tank with member comments as dialog. This year I am taking the club's PAR meter with us and will be doing some readings of member tanks.
> 
> So the data I acquire may be of some relevance to what you have done; along with reading at the substrate level at what other level(s) (depths) did you take readings?


This is a great idea! I hope I can get the data, too. To be most useful you need PAR at the substrate, in the middle, at both ends, and at the front and back of the tank. Plus at least in the middle of the tank at a couple of other distances from the light. Those readings need to be unshaded light, not in the shade cast by the plants. The distances from the light should be measured accurate to about 1/4 inch. And, of course, what light(s) are in use, the type, the manufacturer and model number. For LEDs it isn't practical to record all of the variables - LED part number, LED current, optics used, distances from other LEDs, LED color, etc.

Data from T5NO, PC, and MH lights would be especially useful. PAR from actinic bulbs would be very interesting. And, if possible, the approximate age of the bulbs is useful.


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## killerproblem

I'm going to be setting up my 240g soon, and I'm wanting to make shure that the lights are going to work for it...
tank size: 96L x 18W x 31T
lights will be about 6" above the tank's top ... or about 32-34" from the substrate...

Lighting options available...

I have 2ea: 6 lamp 48" x 18" ea. T8 fixtures (so 12 lamps with full coverage of the tank), these are I-Beam fixtures with polished reflectors (normally used to replace 400w halides in Hi-bays and tall wherehouses)... these I can run any mix of T8NO up to 3x ODNO (I.E. 12x 3lamp ballasts). all these parts are on hand...

and an old 6 lamp 16" x 96" T12 fixture with Pvc pipe reflectors (from when i ran the tank as fish only). sitting on top of the empty tank ATM..

and I have 4ea: 400w MH ballasts I'd have to build / buy exerything for them including needing a chiller for the tank...I'd need new bulbs too, my 14000k are too blue for plants, this gear is left over from when the tank was run as a reef... 

of the options I think the MH's would be way too much light, and the old 6lamp rig is prolly too little... then i guess the question is how to setup the 12 lamp rig...

for T8 lamps I like the sylvania 6500k...or the phillips 6500k, I will not use the GE bulbs as Ive had problems with them in these ballasts. (pulsating and flickering)...

as far as setup of the lights I have 12" to the ceiling above the tank (yes its a tall stand and low ceiling), so not a lot of room to work with...

opinions? sugestions?

Thanx.


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## Hoppy

With that size tank, unless it is in your garage hidden away, I wouldn't even consider a mix of various lights over the tank. You could use two of these, except with only 4 bulbs in them, two at the front, and two at the back, http://www.catalinaaquarium.com/store/product_info.php?cPath=71_136&products_id=1445 Put these in a row across the top of the tank and you should have enough light to grow almost anything, about 40-50 mms of PAR, if you get a good CO2 setup going, which you would need for higher light anyway.


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## offpath

Catalina will also build custom fixtures. I bought one from them a while back for my 210 gallon tank, and I found that with the reflectors and bulbs that they use for their custom builds, I have *well* over 50 mms of PAR running just 4 bulbs at ~36" from the substrate. I bet you could get by with only 3 pairs of 4 ft bulbs over that tank. When I get home, I can provide more accurate numbers if it would help.


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## killerproblem

I wasn't sugesting to mix and match the lights... i was asking if i would be better off using one set or annother... I don't have access to a par meter any more, i can measure lux...
the 12 lamp 3xODNO would (assuming the correct bulbs) run a soft coral reef without any problems, it's about the same output as 4 250w halides. rated lumen output (system output as per spec sheet, using T8-32w 4100k bulbs, and 5000k bulbs) is listed at 21,900Lm for coolwhite and 20,150 daylight. per 6 lamp unit. i should be able to get 30-35k+ Lm runing them as 3xODNO... these also allready have good reflectors, highly polished Al. allmost but not quite a true mirror...

OR using the 400w halides would each output about 35,000Lm with a basic reflector and as mutch as 40,000Lm with a good one, I just would need to buy or build a chiller again... so about $500 - $800 to get them back up and running, more than I wanted to invest in the lights...

dropping over $1000.00 in new lights alone is not something i'd like to do right now, i have 90% of the rest of the equipment I need allready... I was hopeing to spend most of the money on new chems and livestock...
I'm shure the catilina systems are great, but I'm really not after top of the line, or even close, just something to get her back up and running instead of sitting there empty...

this is the type of light i'm wanting to use... i have two of these and 12, 3 lamp balasts sitting around...


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## RickRS

Hoppy said:


> If, by "mirror" reflectors, you mean glass mirrors, those are inferior light reflectors compared even to white paint.


Interesting comment. I'm alway looking for a DIY approach in my hobbies. Was thinking of building a light hood and thought of using glass mirrors for reflectors. The approach would be to use in in a sort of u-channel type configuration like: upsidedown \__/ or \/. So you're saying this is a waste of time compared to just painting the inside of a rectangular light hood box white?


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## Hoppy

RickRS said:


> Interesting comment. I'm alway looking for a DIY approach in my hobbies. Was thinking of building a light hood and thought of using glass mirrors for reflectors. The approach would be to use in in a sort of u-channel type configuration like: upsidedown \__/ or \/. So you're saying this is a waste of time compared to just painting the inside of a rectangular light hood box white?


No, it isn't a mistake to make a \_/ shaped reflector, but use either aluminum or white paint on the reflective surfaces, not glass mirrors, unless they are front surface mirrors.


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## kibri

*Thank You !*

I'm just getting into this planted tank world and was VERY confused by all the information, misinformation, and choices. This thread has given me a good starting point and an understanding of the different kinds of light options.

Thanks to Hoppy and all the others who have contributed to this thread. Hoppy, you have put a lot of time into this and it is greatly appreciated.


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## RickRS

Hoppy said:


> No, it isn't a mistake to make a \_/ shaped reflector, but use either aluminum or white paint on the reflective surfaces, not glass mirrors, unless they are front surface mirrors.


Could you expand on that? What is the issue with regular glass mirrors that would them bad light reflectors?


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## HolyAngel

Mirrors absorb light and don't reflect it. Flat white paint or the dull side of a sheet of aluminum are the best reflective materials you'll find.


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## Hoppy

Mirrors are intended to give an accurate reflection of the light striking them, not to reflect a lot of that light. You can shave by a mirror because of that accuracy - don't try it with a white barn wall:icon_cool


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## kibri

HolyAngel said:


> Mirrors absorb light and don't reflect it. Flat white paint or the dull side of a sheet of aluminum are the best reflective materials you'll find.



The *dull *side of aluminum foil??? 
Wow, that goes against everything my brain has always thought.


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## RickRS

kibri said:


> The *dull *side of aluminum foil???
> Wow, that goes against everything my brain has always thought.


You and me, both! I think HolyAngel is overstating. As to glass mirrors, I can see some light being absorbed by the glass as it travels thru, strikes the silver mirror surface and is reflected out thru the glass a second time. Assuming there's about 5% attenution of the light when it travels thru the glass in one direction, that 10% loss total. But metal surface reflections? AHSupply's highly regarded reflectors are highly polished so they are not dull. If dull was better, won't they save some money in manufacturing by not polishing.

I would like to see some PAR numbers on different reflective surfaces. In fact, any light meter should work for a reflective surface comparsion if the same light source is used in the comparsion. Anyone have links?


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## Hoppy

The difference between highly polished aluminum and unpolished aluminum is the type of reflection, not the percent of the light that is reflected. Polishing gives you specular reflection, unpolished gives you diffuse reflection. If you are trying to concentrate a beam of light some distance away, you can't do it with diffuse reflection. But, for an aquarium I doubt that it makes any real difference. The big difference is when you try to sell a reflector that doesn't look like a reflector.


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## tom855

*Nano Fixture PAR*

I wanted to add two more data points to the thread. I've just started using two different lights for Nano setups, and wanted to pass the PAR readlings along. 

Archaea 27W 10K fixture. Measured in air and inside and empty 5.5G Mini-M with black substrate in the bottom ....... Bottom of light fixture to 12" away reads exactly 40um. Perfect number in my mind.










Also bought a pair of Tensor Vision Max lights for $22 each from Walmart.com. Also available from Bed Bath and Beyond. Similar looking to the Ott Light version at half the cost. Height is not adjustable and there is not an on/off switch. But, the former is overcome by sitting it on something and the latter by using a timer.

8 1/2 to 9 1/2" from the bottom of the fixture (in air) measured 54-45um, respectively. Sitting the light on something could easily get it in the 40-45um range in side the tank.










And on an unrlelated note, I checked to see how the PAR changed when blocking some of the light with a piece of standard fiberglass window screen from Lowes. It knocked the light down by about 40%. I've seen other numbers for this test so it clearly depends on the particular material used in the screen. 

I hope the information is of interest!

Tom


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## Hoppy

That is good data: The Archaea light is a PC light, poor reflector, at best, which falls a little below the PC line on my chart, possibly due to the lack of a reflector. It's the first data point I have for that size bulb.

The Tensor light is a bit confusing. The description and photo look like it is a PC bulb, but the output is consistent with T8 - low for a PC bulb. Is it a typical PC bulb?

One reason why both of those lights gave less than my chart shows is the the chart is based on longer bulbs, and the shorter the bulb, the less efficient it is. I don't think there is much difference between the 36 watt PC bulbs and the longer ones, but shorter than that might be enough lower in efficiency to be significant.


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## tom855

For the Tensor, it's a "Type PL 13W", which appears to be a Compact Fluorescent bulb. From the best I can tell it's a "full spectrum" light, 6400K bulb.

They may not be the most efficient, but they sure put out the perfect amount of light for low/medium light setups.

Tom 

.


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## Ferret

Awesome info, thanks! I was thinking I was in the low light range with my two 22" 24 watt T5HOs on my 29 gallon about 18" above the substrate because it only gave me 1.66 watts per gallon. After reading this though it turns out I'm not, assuming I'm reading this right I should be in the med to high light range correct?


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## Hoppy

Ferret said:


> Awesome info, thanks! I was thinking I was in the low light range with my two 22" 24 watt T5HOs on my 29 gallon about 18" above the substrate because it only gave me 1.66 watts per gallon. After reading this though it turns out I'm not, assuming I'm reading this right I should be in the med to high light range correct?


A single bulb should give you high medium to high light. Two bulbs should give you twice that, which is very high light, too high to easily manage.


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## Ferret

Oh wow, didn't realize I was that high. The fixture I use allows me to control each bulb separately, so I guess I should disable one? Of the two one if is a normal "daylight" (white) and the other is one of the "plant growth" (pink) types, between them which should I leave going? I'm not where I can check but I believe both are the same spectrum.


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## DKRST

Ferret said:


> Oh wow, didn't realize I was that high. The fixture I use allows me to control each bulb separately, so I guess I should disable one? Of the two one if is a normal "daylight" (white) and the other is one of the "plant growth" (pink) types, between them which should I leave going? I'm not where I can check but I believe both are the same spectrum.


I'm in the same boat, same type of bulbs and on/off option. Better to use one bulb? or balance the light spectrum and decrease intensity by raising the fixture it until I'm in the medium intensity range?

_Outstanding research _on the lighting PAR roud:


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## S&KGray

I would say raising the fixture with 2 bulbs > using 1 bulb, but either will work. Your preference depending on color mix, ability to raise fixture high enough, and possibly more light spill into the room.


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## RickRS

Hoppy, the table for fixtures vs. light intensities could use greater explaination. It's clear to me that you must have completely different reflectors with the T8 than the others. Three T8 required to produce the same high light of a single T5NO at 12 inches? I don't think the lumens rating between a T8 and a T5NO is that different for same length. Can you include what type of reflector is assumed in the chart? 

Also, as another variable, what about the difference in tubes? Are all the tubes same 6500k temperature, for example?


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## Hoppy

RickRS said:


> Hoppy, the table for fixtures vs. light intensities could use greater explaination. It's clear to me that you must have completely different reflectors with the T8 than the others. Three T8 required to produce the same high light of a single T5NO at 12 inches? I don't think the lumens rating between a T8 and a T5NO is that different for same length. Can you include what type of reflector is assumed in the chart?
> 
> Also, as another variable, what about the difference in tubes? Are all the tubes same 6500k temperature, for example?


The chart is a first attempt at characterizing typical lights of each type. Typically, T5HO lights have very good single bulb reflectors, with less expensive ones still having very good reflectors, but for multiple bulbs. T8 lights typically have white painted flat surfaces behind the bulbs, but no reflectors to speak of. Non-AH Supply PC lights typically have terrible reflectors. Etc. 

Some one wanting a good project, and with access to lots of different lights can do this over, making distinctions between different manufacturers lights, different bulbs, different reflectors, etc. I can't do that, at least not now.


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## razalas5

Hello Hoppy,
I just need a little help with something. I received this light http://www.bigalsonline.com/productDetailsPage.mtw?productId=7423745 from a friend and was planning on using it over a standard 10g. I assuming this is t5NO and the chart says it would be too high to use sitting directly on top of the tank. Does this mean it's impossible to use? I don't have room for a larger tank and would really hate to see this light go, but I don't want to use it if it causes too many problems.
Thanks


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## pdavis41

It won't be "impossible" to use. Just directly on top of the tank. According to Hoppy's chart, if you suspend the light 12 inches above the tank you will be in the "medium-ish" range.


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## Hoppy

Since that chart was made we have had more data on the Coralife 2 bulb T5NO lights. They aren't nearly as bright as I expected them to be. You can be pretty close to right if you use the T8 line for that T5NO fixture. And, that shows that you can use the light on a 10 gallon tank sitting right on top of the tank.

We also know that many people have had success with that T5NO fixture on 55 gallon tanks, for low light. But, the data shows it producing only about 15 mms of PAR on that height tank. So, the colored ranges for different light intensities needs to be adjusted too. Clearly 15 mms of PAR is still adeuqate for low light, so the lower limit must be at least that low, and recently Tom Barr suggested that even 10 mms is enough for low light. I'm not sure when I will get around to revising the charts though.


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## pdavis41

I missed the NO part. Saw T5 and assumed HO. 

I wish I had a PAR meter to see what I was getting with my PC bulbs on my 75G. I would guess in the 10 to 20 mms range. It was very low light gauging on my plant growth before and after upgrading to T5HO.


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## Rainer

Two T5HOs on top of a 29g falls in the "too high" category. Adding a single layer of window screen would result in "medium" or "high" light?


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## plamski

What about fluorescent plastic shade to lower light intensity and to make light more uniform?


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## Hoppy

I have never tested one of those white diffusers to see what effect it would have, so I wouldn't try it. For one thing, it would interfere with the natural cooling of the bulbs.


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## PelicanFarts

Alright, after reading this thread I'm dropping one 24w T5HO from the top of my 29G tall. Now I have an AquaticLife 2x24w T5HO with individual reflectors sitting 23-25 inches above black substrate. It looks really dim after removing the single 24w, but I'm sure I'll get used to it. 

Now, lets see how many plants I kill!


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## Rainer

Rainer said:


> Two T5HOs on top of a 29g falls in the "too high" category. Adding a single layer of window screen would result in "medium" or "high" light?


Bump


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## Hoppy

One layer of window screen would lower the light to the middle of the high light bracket. Window screen drops the intensity by 40% per layer.


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## Buc_Nasty

I may have missed it but does anyone have data for T5HO lights with high quality reflectors?

I ask because I have two 24 inch T5HO LET retrofit lights with the real high quality reflectors 21 inches above the substrate. According to the chart, this would mean my light is "too high"

What exactly results from "too much" light?


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## fjf888

*retrofiting a cube 16Lx13.5Wx15*

I have 12 gallon cube tank that I want to retrofit with lighting that will grow anything. It will be CO2 injected.

What I thought would make the most sense is an AH Supply CF retrofit kit. Problem is with this tank, I can only fit the 18W, the fixture which is 9.75 inches. Its just slightly too small for a 1x24W which I am fairly confident would be enough light. I'm wondering if the chart would still apply in this case. I could cram 2 in but I think that would be going overboard, especially according to the chart.

Any thoughts greatly appreciated.

Fred


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## Hoppy

Buc_Nasty said:


> I may have missed it but does anyone have data for T5HO lights with high quality reflectors?
> 
> I ask because I have two 24 inch T5HO LET retrofit lights with the real high quality reflectors 21 inches above the substrate. According to the chart, this would mean my light is "too high"
> 
> What exactly results from "too much" light?


The T5HO line on the first chart is for high quality reflectors. "Too much light" means you aren't likely to be able to avoid lots of algae problems, because you can't keep enough CO2 in the water to let the plants grow as fast as the light drives them to without killing the fish. That leads to unhealthy plants, and algae are attracted to unhealthy plants.



fjf888 said:


> I have 12 gallon cube tank that I want to retrofit with lighting that will grow anything. It will be CO2 injected.
> 
> What I thought would make the most sense is an AH Supply CF retrofit kit. Problem is with this tank, I can only fit the 18W, the fixture which is 9.75 inches. Its just slightly too small for a 1x24W which I am fairly confident would be enough light. I'm wondering if the chart would still apply in this case. I could cram 2 in but I think that would be going overboard, especially according to the chart.
> 
> Any thoughts greatly appreciated.
> 
> Fred


A single AH Supply bright light kit would give you high light, but with the short bulb, the ends of the tank would likely be a little lower in intensity. Two of the AH Supply kits would give you way too much light.


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## macclellan

Hoppy said:


>


Who/what decided what counts as "too high", "high", "medium", etc. light in this chart? 

Is the objective: to merely keep plants alive? Avoid algae? Slow, consistent growth? Red reds? Short internode length on stems? Growth maximization?

To say that 4xT5HO is "too high" light for anything under 32 inches of depth is extremely conservative to say the least (ditto for many other examples, such as 2xT5NO over a 12" tank with no co2 or ferts), and seems to be at odds with lots of successful tanks (with varying concepts of success) on this forum. I couldn't imagine trying to keep high light plants under just 2x54w @ 24". I use 4x54w and don't keep "high light" plants. Ditto for when my tank was 20", not 24".

I know I've said similar things in the past, but I like to repeat myself, and there's a new representation in this chart of what seems to me to be well-intentioned, but oversimplified if not misleading advice.


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## MaStErFiShKeEps

We should make a graph chart for CFL bulbs like the one above.


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## plantbrain

macclellan said:


> Who/what decided what counts as "too high", "high", "medium", etc. light in this chart?


It is arbitrary. We need to pick and chose _something_.
What is the min light you can grow 95% of all plants? 20-35micromols.
That is less arbitrary.

What is the max level of light that will no longer increase growth independent of CO2 and nutrients? About 400-600 micromol, not many will fine this fun however.

If CO2 and nutrients are non limiting, then adding 2-3x more light will increase the rates of growth enormously. 

A good ideal light level will minimize and increase the light use efficacy independent of other factor AND........also demonstrate at a very high level of skill for scaping (Horticulture/landscaping design) 

This seems to be about 40-50micromoles.
This was done by testing people's aquarium who have placed very high in the contest etc.



> Is the objective: to merely keep plants alive? Avoid algae? Slow, consistent growth? Red reds? Short internode length on stems? Growth maximization?


Best management practice.
One where managing CO2 and fish health, algae and ease of keeping the plants yields the highest % of success for a nice scaped tank and with the widest no# of species for the largest % of aquarist.
We cannot ignore fish and general care /labor from the aquarist.

In otherwords, let me turn this around on you:
What is the maximum no# of fish that you can possibly add to the tank?
What is the most amount of food can you feed them?
What is the max growth rates can I obtain with the fish?
What is the best CO2 level for fish?

Is "more" wise/better and even should it be suggested to the general hobby this way??

Perhaps for specific folks who might enjoy playing with fire or experienced folks with specific goals. However, for the average folks that includes say 90% or more?



> To say that 4xT5HO is "too high" light for anything under 32 inches of depth is extremely conservative to say the least (ditto for many other examples, such as 2xT5NO over a 12" tank with no co2 or ferts), and seems to be at odds with lots of successful tanks (with varying concepts of success) on this forum.


Just because someone happens to have more light does not imply that (they have measured it??) it required for their results. If they measured it and reduced it down to see what their minimum might be, then you can say something, argue for it etc.

I know of no scape or plant I cannot grow WELL under the light chart Hoppy suggest, not one species. 



> I couldn't imagine trying to keep high light plants under just 2x54w @ 24". I use 4x54w and don't keep "high light" plants. Ditto for when my tank was 20", not 24".


I honestly do not quite know what a "high light plant is"
What is the min amount required?
Do you know the answer?
Is it independent of nutrients and CO2?
How would you confirm and calibrate the CO2 method?

This is not as easy to answer as it might seem.

You have to try it and see, if someone can show they grew the plant at say 30 micromol and you could only do it with 60, then your claim would be falsified. You can say that was the lowest you where able to do so....but you cannot say it is the lowest, the no#'s Hoppy and I suggest often times are the lowest we have observed..........they might be lower even still.........

That remains untested and demonstrated.
When someone claims that x species cannot be grown at less than say 50micromoles, *this is a very easy question for others to test and confirm or falsify.*

All it takes is one or two folks and that hypothesis is cooked and refried.



> I know I've said similar things in the past, but I like to repeat myself, and there's a new representation in this chart of what seems to me to be well-intentioned, but oversimplified if not misleading advice.


Well, that is a trade off, I think we all like simple easy to understand things.
However, when this is done.......there are things that get left out of the model.

That is the very nature of simplifying complex things.

*What might you suggest constructively that would not be too complex and yet useful to add to the chart?*
Better Hoppy than me I say He wants to do it, has the passion to make and share these charts etc......bully for him, I have the meter so I'm happy. 

Look, this is 100X better than W/gal or watt/gallon converters I've seen.....but I understand many are not going to use/buy PAR meters also, so this is the next best thing, but I like to use a meter and test myself. I'm curious and ignorant of how low we can go.........and we also know that lower light requires less CO2 and nutrients, which inherently implies........ easier management.

Hence Hoppy's advice for the chart.
Intermediate folks, they can mess around more if they chose.

No one is suggesting otherwise here.


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## chad320

+2 :hihi:


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## Buc_Nasty

x2

Haha as I was literally in the middle of typing a post to try to somehow tell Mclellan to relax and try to convey how unless we are Tom Barr or Takashi Amano or something than Hoppy's chart is unbelievably useful, who posted a response that outdid mine by 1000 times? Tom Barr. 

Unless you want a 30 page guide with a ridiculous amount of specifics on each of the probably hundreds of other factors, and have all day to dink around with your plants like Mclellan apparently does, Hoppy's chart is $$$.


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## Rainer

Okay, so we have a minimum PAR value for 95% of plants to grow. Obviously I don't want high light if it's unnecessary but I want enough to bring out the colors of L. aromatica and L. repens "Rubin", for example. Is there a rough minimum number for 95% of non-green plants?


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## gene4christ

OK, If I understand this right two 2x48" T5no fixtures on my 75gal. will give me low/med if I put on glass top, one at front and one at back of the tank do I have that right ?


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## kirk

I'm a planted tank beginer even though i had thoughts of doing this twenty years ago. Life changed and here i am fulfilling that old dream. Thanks Hoppy and all here who make this lighting thing more understandable!

Ive read all 25 pages of this thread here so far and still wonder, if i've chosen the right light or not. I researched my lighting needs enough i thought - a low maintenace tank, no CO2, maybe diy CO2 someday but was looking for high side of low or low side of med. say 50 microm's... i figured ~ 2 watts per gallon. i Found AH supply a local for me lighting store option and was sold on the 96 watt 34" PC w/ qaulity reflector. So anyway i think i burned my java ferns, prompted a cyano bacteria bloom and broke the new glass top for my 46 gal bowfront! :icon_eek: From the heat that is!

I understand watts per gal. does not work but that's what Ah supply sold me. Maybe that's ok. That leads to my question.

I see on the chart that the AHS PC lighting is less than the t5HO lighting. That maybe so but i found this here on PTF. It was posted by "Zulu" and the entire post can be found under "T5/T5HO vs Compact Fluorescent/Power Compact". Here it is:



"Hi Iggy,

The info below should answer your questions more clearly. My other comments about CF being 2x T12 (reg. fluorescent) were very generic and depend on various factors. 

The disclaimers are:

- watts/gallon is, at best, a marginal rule of thumb
- watts/gallon makes no comment on the light wavelengths present for chlorophyll activation or aesthetic viewing of your plants and fish
- watts/gallon does not account for tank depth or area of coverage
- watts/gallon does not account for bulb efficiency
- watts/gallon is mired in word-of-mouth confusion and does not readily account for technological advances in lighting

Different bulbs have different specs and you should research the products you are buying. If a manufacturer won't provide the specs, then don't buy their product.

*Comparison of Sylvania Bulbs to Help Show Differences Among T12, T8, T5, T5HO, and CF Lighting*

NOTE: Sylvania does not make a 96w 36" CF bulb - data is from a generic, probably Panasonic, bulb

*Standard T12 Lighting*
bulb: F30T12/CW/RS 
power: 30w
length: 35.78"
life: 18000 hrs.
av. lumens: 1870
lumens/watt: 62.3

(note: there are 3' supersaver versions of T12 that use 5 less watts and have an av. lumen output of 1636 - not worth comparing.)

*Standard T8 Lighting*
bulb: FO25/730
summary for this bulb: 18.5% more economical for similar light output at the same bulb length
power: 25w
length: 35.78
life: 20000 hrs. (11.1% better)
av. lumens: 1845
lumens/watt: 73.8 (18.5% better)

For this T8 bulb, the difference compared with T12 is that it uses 5 less watts to produce equivalent light (19% savings) with a bulb diameter that is 33% smaller, which means that more of them will fit in a hood. This bulb also has a longer rated life.

*Standard T5 Lighting*
bulb: FP21 (PENTRON T5)
summary for this bulb: 30-50% more economical for the similar light output at the same bulb length
power: 21w
length: 34"
life: 20000 hrs. (11.1% better)
av. lumens (at 25c): 1758
lumens/watt (at 25c): 83.7 (34% better)
av. lumens (at 35c): 1953
lumens/watt (at 35c): 93 (49% better)

For this T5 bulb, the difference compared with T12 is that it uses 9 less watts to produce equivalent light (30% savings) with a bulb diameter that is almost 60% smaller, which means that more of them will fit in a hood. This bulb also has a longer rated life.

*T5 HO Lighting*
bulb: FP39/841/HO (PENTRON T5 HO)
summary for this bulb: 15-34% more economical for 50-75% more light output at the same bulb length.
power: 39W
length: 34"
life: 20000 hrs. (11.1% better)
av. lumens (at 25c): 2803
lumens/watt (at 25c): 71.9 (15% better)
av. lumens (at 35c): 3255
lumens/watt (at 25c): 83.5 (34% better)

For this T5 bulb, the difference compared with T12 is that it uses 9 more watts (30% more energy) and produces 50-70% more light. As above, the bulb diameter is 60% smaller and the bulb has a longer rated life.

*Compact Fluorescent - Twin Bulb - Similar Wattage*
bulb: FT36DL/835 (Dulux L) (uses T5 bulb diameter for a total width slightly wider than T12)
summary for this bulb: 11% more economical for 33% more light output at less than 1/2 the same length.
power: 36W
length: 16.6"
life: 12000 (33% worse)
av. lumens: 2494
lumens/watt: 69.3 (11.2% better)

For this CF bulb, the difference compared with T12 is that it uses 6 more watts (20% more energy) and produces 33% more light. The bulb diameter is slightly wider than a T12 (+.5") and the bulb has a shorter rated life. However, in this case, the overall bulb length is less than 1/2 as long.

*Compact Fluorescent - Twin Bulb - Higher Wattage, Slightly Longer*
bulb: FT55DL/835 (Dulux L) (uses T5 bulb diameter for a total width slightly wider than T12)
summary for this bulb: 20% more economical for 121% more light output at 60% of the same length.
power: 55W
length: 21.1" (still much shorter overall)
life: 12000 (33% worse)
av. lumens: 4128
lumens/watt: 75 (20.4% better)

For this CF bulb, the difference compared with T12 is that it uses 25 more watts (83.3% more energy) and produces 121% more light. The bulb diameter is slightly wider than a T12 (+.5") and the bulb has a shorter rated life. However, in this case, the overall bulb length is 60% of a 30w T12.

*Compact Fluorescent - Twin Bulb - Higher Wattage, Similar Length to 30w T12*
bulb: Generic 96w CF (uses T5 bulb diameter for a total width slightly wider than T12)
summary for this bulb: 20% more economical for 333% more light output at 95% of the same length.
power: 96W
length: 33.85" (still slightly shorter overall)
life: 12000 (33% worse)
av. lumens: 8100
lumens/watt: 84.4 (35.4% better)

For this CF bulb, the difference compared with T12 is that it uses 66 more watts (220% more energy) and produces 333% more light. The bulb diameter is slightly wider than T12 (+.5") and the bulb has a shorter rated life. The overall bulb length is roughly equivalent to a 30w T12 (95%).

...and just for laughs:
*Double-ended Metal Halide HID*
bulb: HQI-DE250/NDX 
summary for this bulb: This bulb is roughly equivalent in efficiency to 9 30w T12's with 756% more light output than a single 30w T12 which it accomplishes in 6.5" of space with a lower life expectancy (but similar replacement interval).
power: 250W
length: 6.5"
life: 10000(45% worse)
av. lumens: 16000
lumens/watt: 64 (2.7% better)

Lumens are an indication of light as seen by humans, not plants, but I used it to try and help you see the differences in bulb output."



The 39 watt 34" t5ho gives approx. 3000 lumens while the 96 watt 34" PC gives 8100 lumens. 8100 lumens is more than 4x as bright as what i had - A T8 giving 1845 lumens. That is way to much light, right:icon_ques

I'm thinking a single t5ho bulb might still be too much light at 18" to substrate. This is what gets me. the 96 watt PC bulb is still more than twice as bright as the single 39 watt t5HO. But your chart says different. That the ahs PC is lower lighting than the single t5ho:icon_ques Is it because the PC is a twin and the T5HO is single linear? Are the lumens to PAR that different?

I feel i wasted my money on the PC light kit and would like to be able to use the fine reflector and the workhorse 5 ballst. I can use a single t5ho w/ this ballst but not the lower light t5's. I would only retrofit a t5ho if it was much less brighter than the 96 watt PC as i would like to keep the tank on the low tech side of things although i hooked up a modest DIY CO2 system on the recently cycled tank.

Thank you so much and i hope this post helps

Kirk


----------



## Hoppy

gene4christ said:


> OK, If I understand this right two 2x48" T5no fixtures on my 75gal. will give me low/med if I put on glass top, one at front and one at back of the tank do I have that right ?


Here is the chart from page one of this long thread, the latest version:









Note that T5NO typical light fixtures are about the same as typical T8 light fixtures. A two bulb T5NO light will only give you low light on that tank. And, two widely spaced ones will give you low light that is pretty uniform over the whole substrate. This is based on recent data reported here on TPT plus the knowledge that people successfully use Coralife 2 x T5NO lights on 55 gallon tanks for low light.


----------



## Buc_Nasty

In response to Kirk about PC vs T5HO with high quality reflectors...I did exactly what you did...wasted my money on Power Compacts.

I was a complete noob to aquariums and asked a LFS which lights they made their tank look so good with and they said PC so I nubbishly dropped $130 each on two coralife double 24 inch PC lights, one one either end of my 125 gallon with no light in the middle. I put them right on the lids, and they got so hot they fricken cracked my lids. They also heated up the tank so much in the summer that I had to shut them off for 5 hours midday b/c they were makin my tank like 90 fahrenheit and heating up the entire room like a sauna.

My plants didnt grow well except for a big aponogeton, and i started learning a lot more about lighting and found out that T5HO with good reflectors are SO much better than PC.
I managed to sell the PC's for a little less than I bought them for, and got the LET retrofit T5HO kit from reefgeek. ...same setup as PC, 2 bulbs on either end of my 125g.
My plants started growing like nuts, within a week the stargrass that was almost dead tripled in size and was all green. 

The stats for my particular setup:
PC initial cost $260 for two 24 inch coralife double PC fixture
192 total watts - running 8 hrs a day costs $85 a year electricity to run
supposed to change bulbs every 6-12 months for 4x $25+ 
nowhere near the light penetration or plant growth
heat cracks lids if directly on them, boil water, turn room into sauna
Fixtures run really loudly
Rough estimate $140 a year to run


T5HO initial costs
$275 for 4 24 inch bulbs, 2 high quality ballasts, 4 highest quality reflectors, all endcaps and wiring from reefgeek.com
$8 DIY cooling fans
92 total watts - $42 in electricity per year to run 8 hrs a day
suppsed to change bulbs 18-24 months for 4x $10-$15
WAY better plant growth than comparable PC
no heat issues super cool
very quiet
Rough estimate $60 a year to run


----------



## Hoppy

kirk said:


> I'm a planted tank beginer even though i had thoughts of doing this twenty years ago. Life changed and here i am fulfilling that old dream. Thanks Hoppy and all here who make this lighting thing more understandable!
> 
> Ive read all 25 pages of this thread here so far and still wonder, if i've chosen the right light or not. I researched my lighting needs enough i thought - a low maintenace tank, no CO2, maybe diy CO2 someday but was looking for high side of low or low side of med. say 50 microm's... i figured ~ 2 watts per gallon. i Found AH supply a local for me lighting store option and was sold on the 96 watt 34" PC w/ qaulity reflector. So anyway i think i burned my java ferns, prompted a cyano bacteria bloom and broke the new glass top for my 46 gal bowfront! :icon_eek: From the heat that is!
> 
> I understand watts per gal. does not work but that's what Ah supply sold me. Maybe that's ok. That leads to my question.
> 
> I see on the chart that the AHS PC lighting is less than the t5HO lighting. That maybe so but i found this here on PTF. ............
> 
> Kirk


There is a lot more to aquarium lights than bulbs producing X lumens. By far the most important part of aquarium lights is the reflector or reflectors. AH Supply lights are so good because they use very good reflectors, well designed reflectors that allow plenty of room around the bulbs for light from the back of the bulb to be directed towards the tank. Coralife T5NO lights have very poor, almost ineffective reflectors because they don't provide that room. Virtually all T8 lights have no reflector at all, just white painted interior parts that reflect a little of the light otherwise lost. And, high quality T5HO lights have individual reflectors for each bulb, that increase the amount of usable light by about a factor of about 2.5 to 3. 

PC bulbs, the two parallel tube type that AH Supply kits were made for, cannot use as efficient a reflector as a good quality T5HO light uses. So, even if the bulbs were as bright as the T5HO bulbs, and I don't believe they are, you can't get as much of the light from the bulbs to the tank. PC bulbs are also much shorter than T5 bulbs, so they can't light nearly as much of the tank. So, it takes two PC bulbs to cover as much of the tank as one T5HO bulb.

All of the lumens data in the world will not substitute for actual PAR readings. Lumens is the total amount of human eye visible light emitted by a bulb. PAR is the actual plant usable light per unit area at a certain distance from the bulb. Apples and oranges - more accurately, apples and beets.


----------



## kirk

Thanks folks,

So Hoppy, even though the 96 watt is 34" long, just as long as the 39 watt t5ho bulb it's less bright in PAR but more than 2.5x as bright in lumens??

I certainly could be wrong but it seems to me that the *twin 96 watt 34" PC* is twice the bulb physically as the *single 39 watt 34" t5HO* bulb. (Keep in mind i'd be using the nice reflector from AH supply.) So the pc bulb even still is less bright in PAR?

What would a t5 or t8 bulb produce in PAR with AHS reflector. 40% more as in earlier posts?

BTW: just to be clear AHS did not sell me via watts/gal. - I just meant that they _might_ have sold me too much light for my needs?? "I understand watts per gal. does not work but that's what Ah supply sold me. Maybe that's ok. That leads to my question."

thanks again,
kirk


----------



## Buc_Nasty

kirk said:


> Thanks folks,
> 
> So Hoppy, even though the 96 watt is 34" long, just as long as the 39 watt t5ho bulb it's less bright in PAR but more than 2.5x as bright in lumens??
> 
> I certainly could be wrong but it seems to me that the *twin 96 watt 34" PC* is twice the bulb physically as the *single 39 watt 34" t5HO* bulb. (Keep in mind i'd be using the nice reflector from AH supply.) So the pc bulb even still is less bright in PAR?


Hoppy knows the numbers but I'll tell you right now that sounds right. My PC fixtures lit the entirety of the tank (and room) more, but in terms of plants weren't doing much at all even tho they look so much brighter. 
I probably read this in a Hoppy post originally but just the physical design of a PC bulb makes it so a lot of light is wasted...with a single reflector on a T5 the light going in all directions is redirected downwards. PC bulbs are fatter, blocking more reflected light, and have two next to each other so all the light shining into each other is wasted.


----------



## kirk

Thanks Buc Nasty

Wow, so it looks like i can not use the "workhorse 5" ballast that the kit came with because i will have to use the lower power lights such as the t5NO or T8's but with a good reflector of course 

kirk


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## kirk

Anyone in the market for one 96 watt twin retro kit?

i'm thinking the 96 watt PC or the t5HO is going to be too much light for my needs on the 46 gal. bowfront. (substrate 18" from top of tank.) i'd like to keep the light right on top of the tank...


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## Buc_Nasty

I just re-read your post...your lid cracked too!! PC's are just so useless...take so much electricity, so much heat, and dont even grow plants that well! In the long run its not even worth using them even if you've already bought them lol just try to sell them on craigslist...hype them up and say they make evreything look great and grow plants well and hope u find a nub like I did who doesnt know the whole story. I sold my fixtures for $110 each after payin $130 each.


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## kirk

maybe just a bright shop light for task lighting and a little supplemental heat...ha ha


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## Hoppy

kirk said:


> Thanks folks,
> 
> So Hoppy, even though the 96 watt is 34" long, just as long as the 39 watt t5ho bulb it's less bright in PAR but more than 2.5x as bright in lumens??
> 
> I certainly could be wrong but it seems to me that the *twin 96 watt 34" PC* is twice the bulb physically as the *single 39 watt 34" t5HO* bulb. (Keep in mind i'd be using the nice reflector from AH supply.) So the pc bulb even still is less bright in PAR?
> 
> What would a t5 or t8 bulb produce in PAR with AHS reflector. 40% more as in earlier posts?
> 
> BTW: just to be clear AHS did not sell me via watts/gal. - I just meant that they _might_ have sold me too much light for my needs?? "I understand watts per gal. does not work but that's what Ah supply sold me. Maybe that's ok. That leads to my question."
> 
> thanks again,
> kirk


A PAR meter doesn't lie  Much of the AH Supply data I have is from my own lights. I have had 55 watt and 36 watt kits, with 6700K, 8725K and 10,000K bulbs. The PAR vs distance data falls on virtually the same curve for all of them. 96 watt AH Supply kits are just longer versions of the same light. So, I'm very confident about the curve on the chart for those lights.

The T5HO data comes from several other people, and various manufacturers, and various numbers of bulbs per fixture. That data does have a lot of scatter, because not all reflectors are equally good, but that curve seems to fit most of the data, so I'm pretty confident about it too. Unfortunately, I don't have much data for Catalina lights or single reflector cheap lights. I am assuming they will give somewhat less PAR per bulb, but I don't know how much less.

I like AH Supply lights, which is why I have so much data from them. They are very good lights, but they do heat up the water a bit, and I think they do best when hanging a few inches above the tank. I don't like the Coralife PC lights, even though I have never had one. Just by looking at them you can see that their reflectors are not good, which is pretty shoddy cost savings in my opinion.


----------



## kirk

Wow simply amazing.

i like ah supply - nice reflectors but it looks like that info settles it for me then. I have too much light and the t5HO will be even more.

So it looks like i'm looking for a double T8 stock aquarium hood or a single T5NO w/ a good reflector in the hood. i think i prefer the later... less watts.

Does that sound about right Hoppy? That is for 30 - 50 micromols @ 18" from substrate. 46 gallon bowfront. Would a single t5NO w/ a nice reflector do it ya think?

better to have lower light and maybe some CO2 here and there than more light and no CO2. Or even much more light CO2 ferts and a delicate balancing act. At least for me...

Thanks! This thread been great for me on clearing up some misconceptions i had that the more light the better.


----------



## Hoppy

If you use a T5NO bulb and ballast, with a T5HO single bulb reflector, you should get about half the PAR as the curve on that chart shows for T5HO. So, yes, that setup should give you around 40 mms of PAR at 18 inches. I think it might be difficult to find such a light retrofit kit, but you should be able to mix and match parts to make one.

Eventually I think we will all realize that low to medium light, with good CO2 is the ideal planted tank setup. The best of both worlds.


----------



## kirk

*Wow*



Hoppy said:


> There is a lot more to aquarium lights than bulbs producing X lumens. By far the most important part of aquarium lights is the reflector or reflectors. AH Supply lights are so good because they use very good reflectors, well designed reflectors that allow plenty of room around the bulbs for light from the back of the bulb to be directed towards the tank. Coralife T5NO lights have very poor, almost ineffective reflectors because they don't provide that room. Virtually all T8 lights have no reflector at all, just white painted interior parts that reflect a little of the light otherwise lost. And, high quality T5HO lights have individual reflectors for each bulb, that increase the amount of usable light by about a factor of about 2.5 to 3.


So if i had a single t5NO (not HO) with an excellent AHS reflector then would that meet my above quota? So 2.5 to 3x is that the same for t5NO?



Hoppy said:


> All of the lumens data in the world will not substitute for actual PAR readings. Lumens is the total amount of human eye visible light emitted by a bulb. PAR is the actual plant usable light per unit area at a certain distance from the bulb. Apples and oranges - more accurately, apples and beets.


Amazing the difference - when a light in lumens is more than 2.5x as bright but not as bright in PAR. Just didn't think it likely. I'm glad i asked:icon_eek:

i suppose another option would be to just raise the 96W PC ~4" above the tank. It would give more even lighting but @ double the watts and i prefer the glowing cube look.

Good going Hoppy!

Kirk


----------



## kirk

Hoppy said:


> If you use a T5NO bulb and ballast, with a T5HO single bulb reflector, you should get about half the PAR as the curve on that chart shows for T5HO. So, yes, that setup should give you around 40 mms of PAR at 18 inches. I think it might be difficult to find such a light retrofit kit, but you should be able to mix and match parts to make one.
> 
> Eventually I think we will all realize that low to medium light, with good CO2 is the ideal planted tank setup. The best of both worlds.



Alright, good to hear. i have no prob modding. Maybe sell the bulb and ballast or to the work shop w/ it. Always looking for good light in the work shop...

Thanks again Hoppy

kirk:thumbsup:


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## lauraleellbp

Hey Hoppy a friend of mine is bugging me to ask you- are your PAR measurements supposed to be micromols per square cm or per square m?


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## macclellan

Hoppy said:


> Unfortunately, I don't have much data for Catalina lights


 I wonder if that's (part or all) of the source of our disagreement, that the catalina fixture with catalina bulbs aint that bright. the PAR measurements I made and have posted here @pt differ from yours.

I'll take more PAR measurements on my 24" tall 90g with giesemann bulbs in the same fixture once I get the meter from the local club.

cheers.


----------



## macclellan

lauraleellbp said:


> Hey Hoppy a friend of mine is bugging me to ask you- are your PAR measurements supposed to be micromols per square cm or per square m?


 it says per square cm right on the chart.


----------



## DKRST

For those of us who, unfortunately, didn't invest in the best-quality T5HO fixtures and purchased what was to be found at the LFS (i.e. Aquasun), how much should we shift "down" on the PAR chart to estimate our actual lighting levels - A T5HO bulb with a fair(?) reflector. Would those T5HO's PAR output be closer to the AHS PC line or somewhere in-between?


----------



## waters10

macclellan said:


> I wonder if that's (part or all) of the source of our disagreement, that the catalina fixture with catalina bulbs aint that bright. the PAR measurements I made and have posted here @pt differ from yours.
> 
> I'll take more PAR measurements on my 24" tall 90g with giesemann bulbs in the same fixture once I get the meter from the local club.
> 
> cheers.


Yeah, I tried to find PAR measurements on the catalina fixtures and didn't come up with a lot results. The ones out there (including yours) indicate lower PAR than Hoppy's chart. I wonder if this is related to the bulbs themselves or their reflectors. Based on all the praise they get, I think it's more about their bulbs.

I just changed my photoperiod to use all 3 bulbs in my 3x54W Catalina, instead of 2 in my 85 gallon tank. All catalina bulbs.


----------



## macclellan

waters10 said:


> Yeah, I tried to find PAR measurements on the catalina fixtures and didn't come up with a lot results. The ones out there (including yours) indicate lower PAR than Hoppy's chart. I wonder if this is related to the bulbs themselves or their reflectors. Based on all the praise they get, I think it's more about their bulbs.
> 
> I just changed my photoperiod to use all 3 bulbs in my 3x54W Catalina, instead of 2 in my 85 gallon tank. All catalina bulbs.


 They are praiseworthy fixtures even with the OEM bulbs due to their cost-to-performance ratio and build quality. I am not sure if it is the bulbs or not that accounts for the difference. I'll have to test and find out. 

Your experience matches mine. I think that the Catalina 3 bulb fixtures - which, unsurprisingly, they call their "Planted Aquarium" fixture - are ideal for most people seeking moderate light (2 most of the time with a +1bulb burst, or all 3 on taller tanks) on 20"-30" tall tanks. 2 bulbs just isn't enough, IMHO, and the cost difference between the 2x and the 3x is trivial (for the 48" fixtures, they are $125 and $139 respectively). 4 is perhaps a bit more than needed for many, but it is easier to turn a bulb off or reduce a photoperiod than to have less light than you need/want and have to upgrade your fixture (which I would have done by now had I gotten their 2xHO). Luckily, I got mine back when the 4x were $150.


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## Rainer

Ignore - not pursuing that option.


----------



## jonathandowers

Hoppy said:


> I have been wondering how much PAR a typical T12 light produces. Like most everyone else I have just assumed that watts per gallon was a way to guess the light from T12 bulbs, but there is no more reason to expect that to mean anything than there is to expect it to mean anything for other bulb types. So, I decided to do some testing.
> 
> I borrowed a new two bulb 48 inch T12 light fixture from one of our local aquatic plant club members, bought a new T12 bulb - a Phillips "Natural Sunshine", 40 watt 5000K, 92 CRI bulb at HD, borrowed our club PAR meter and took some readings. Since I have previously found that I get virtually the same readings with water in the tank and with air in the tank, I omitted the water this time. Then I plotted my smoothed data on a common plot with T5 and PC data:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> To compare this with "watts per gallon", I know that a couple of 2 bulb T12 fixtures will grow plants in a 55 gallon tank. That tank is 20 inches deep, so if the substrate thickness is about the same as the height of the bulbs above the top of the tank, each bulb should give about 9 micromols of PAR, or 36 micromols for 4 bulbs. That is right in the middle of the low light range. So my data is consistent with real life results.
> 
> The light fixture I borrowed has an acrylic splash shield and a removable back, which is a white reflector. I tested the light with and without the splash shield to find that the shield reduces the intensity about 7%. Testing with and without the white "reflector" shows that the reflector increases the intensity by about 36%. The data used for the chart is with both the shield and the reflector.
> 
> Some popular tanks are only 12 inches high. For those tanks T12 bulbs should give about 25 micromols per bulb, so a 2 bulb fixture will give low medium light intensity, probably a good choice for many people with one of those tanks.
> 
> I believe T8 bulbs produce about the same amount of light as T12 bulbs, but at a lower wattage, because they are more efficient. The fixture I borrowed uses starters and magnetic ballasts, so I didn't try it with a T8 bulb.
> 
> EDIT: Updated chart above and added the following chart:
> Another way to use this is to convert it into a simple table, that lets you select a lighting option based on tank height, how high you want the light to be above the top of that tank, and how much light you want. This assumes that multiple bulbs are mounted close together, reflectors are typical for that particular type of light. And, I left out the AH Supply light kits.


Ok, I'm going to go against the grain and say this experiment is dubious, and needs extensive clarification. 

First off, you have a t12 fixture with a t12 bulb. Why are the results in T5 and T8? You can't just swap out the bulbs; each type require different ballasts. There was no mention of how you measured those other bulbs; thus, I assume you tried putting in t5 bulbs into a t12 fixture. No idea how.

Why aren't the types of reflectors and specific models listed? What defines a "poor" reflector? 

While the results presentation looks pretty, the procedures are undocumented and rather hand wavvy (no, I'm not talking about t-values either).

I have worked as a researcher at several prestigious labs. So I do have higher standards when reading and analyzing results. Taken alone, these results do not make sense to me.


----------



## Buc_Nasty

jonathandowers said:


> Ok, I'm going to go against the grain and say this experiment is dubious, and needs extensive clarification.
> 
> First off, you have a t12 fixture with a t12 bulb. Why are the results in T5 and T8? You can't just swap out the bulbs; each type require different ballasts. There was no mention of how you measured those other bulbs; thus, I assume you tried putting in t5 bulbs into a t12 fixture. No idea how.
> 
> Why aren't the types of reflectors and specific models listed? What defines a "poor" reflector?
> 
> While the results presentation looks pretty, the procedures are undocumented and rather hand wavvy (no, I'm not talking about t-values either).
> 
> I have worked as a researcher at several prestigious labs. So I do have higher standards when reading and analyzing results. Taken alone, these results do not make sense to me.


You are of course right, but you cannot deny that this chart is far better than that traditional "watts per gallon" garbage. If this forum was a prestigious lab where people were being paid to experiment and test, than I completely agree with you. Hoppy did this during his own free time tho. 

With that said, Hoppy if you included brands and models, it would be a lot more useful as we both know that the same product can vary a whole lot across brands. If you own all the different lights you used or remember which products exactly, a list would be appreciated by everyone reading this thread. Just throwin it out there.


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## houseofcards

Well based on recent member PAR readings of various T5HO fixtures I can only conclude two things. 

1. The PAR values of different brands of T5HO fixtures vary greatly since some achieved readings that will categorize their tanks anywhere from low to high light with the same bulb configuration.

2. The PAR readings were obtained differently, thus rendering the numbers meaningless. 

Either way I do agree that many brands of fixtures need to be tested under the same conditions to make this data more reliable.


----------



## shortsboy

Is there anyone here that works at a LFS and has a PAR meter who'd be willing to spend an evening for our benefit testing lamps and bulbs? I'd kick in a couple of bucks for their time if we could get a broad cross-section of currently available products.

Heck, I'd offer my time on a weekend, except I don't have the meter of the lights (hence the LFS mention).


----------



## Buc_Nasty

Theres got to be a LFS owner or someone on here that has access to a bunch of the different types of lights. 
He or she needs to go ahead and test all of them under the same conditions at all the different heights and whatnot and make a nice chart with all the models and everything. 
So much easier said than done haha. Altho I did something similar with pumps I had access to here: http://www.monsterfishkeepers.com/forums/showthread.php?t=401231
but nobody has even replied haha


----------



## Higher Thinking

jonathandowers said:


> Ok, I'm going to go against the grain and say this experiment is dubious, and needs extensive clarification.
> 
> First off, you have a t12 fixture with a t12 bulb. Why are the results in T5 and T8? You can't just swap out the bulbs; each type require different ballasts. There was no mention of how you measured those other bulbs; thus, I assume you tried putting in t5 bulbs into a t12 fixture. No idea how.
> 
> Why aren't the types of reflectors and specific models listed? What defines a "poor" reflector?
> 
> While the results presentation looks pretty, the procedures are undocumented and rather hand wavvy (no, I'm not talking about t-values either).
> 
> I have worked as a researcher at several prestigious labs. So I do have higher standards when reading and analyzing results. Taken alone, these results do not make sense to me.


Well since you have worked in such prestigious laboratories perhaps you would be interested in providing us with a more acceptable table of information?


----------



## Nate McFin

Higher Thinking said:


> Well since you have worked in such prestigious laboratories perhaps you would be interested in providing us with a more acceptable table of information?


 lol...roud:


----------



## Hoppy

jonathandowers said:


> Ok, I'm going to go against the grain and say this experiment is dubious, and needs extensive clarification.
> 
> First off, you have a t12 fixture with a t12 bulb. Why are the results in T5 and T8? You can't just swap out the bulbs; each type require different ballasts. There was no mention of how you measured those other bulbs; thus, I assume you tried putting in t5 bulbs into a t12 fixture. No idea how.
> 
> Why aren't the types of reflectors and specific models listed? What defines a "poor" reflector?
> 
> While the results presentation looks pretty, the procedures are undocumented and rather hand wavvy (no, I'm not talking about t-values either).
> 
> I have worked as a researcher at several prestigious labs. So I do have higher standards when reading and analyzing results. Taken alone, these results do not make sense to me.


For the T5 and T8 bulbs, I just held one end of the bulb in my left hand, and the other end in my right hand. Then I stuck my toe in the electric socket. My eyes registered the amount of light.

Seriously, are you really thinking that I have no idea that I can't stick a T5 bulb in a T12 fixture?

The data behind these charts is from several different people, who either reported it in a forum, or sent me the data personally. There were several different manufacturers T5HO fixtures, from Tek to Catalina, and several different lengths of bulbs, from 2 foot to, as I recall, 6 foot, and several different numbers of bulbs per fixture, from 1 to at least 4. All of this data simply made a bunch of apparently random points on a graph.

From that start, I tried several ways of "normalizing" the data, and quickly found that the PAR produced followed the inverse square rule reasonably well, and that for most fixtures 2 bulbs gave twice the PAR as on bulb, etc. Soon after that I noted that 2 foot and 4 foot bulbs gave the same PAR directly under them, at the same distance. I also noticed that it is hard to get two consecutive PAR readings to be identical, due mostly to variations in operator errors, so any PAR data is likely to have significant scatter.

I am a big fan of log log graphing of data, because it makes it easy to see when one variable is proportional to a power of another variable. I used log log graphing intensively in doing all of this. I also use that graphing to allow me to further normalize data to get equivalent values at some specific condition. My T5 charts came out of all of this.

I had two AH Supply PC lights on my tanks, so I used them to get PAR data for that type of fixture, and got additional data from others.

For the T12/T8 data, I borrowed a T12/T8 2 bulb fixture, and used a new T12 bulb in it. It was a typical fixture for that type of bulb. 

You asked what a poor reflector is. A good reflector, based again on my own experience, is one where when you look at the bulb(s) in the fixture, you see extra bulbs, making it confusing to tell just how many bulbs are really there. In fact, a good reflector shows nearly perfect images of the bulb on both sides of the real bulb, or even 2 such images. Those images provide light just as the real bulb does. That's why an AH Supply reflector, for example, can give you nearly 3X the light that a bare bulb gives. And, from my experiments I know that even a very simple \_/ shaped reflector will double the light from a bulb. This requires that the reflector be enough wider than the bulb for those reflections to show, and for the reflective surface to be polished aluminum. A "poor" reflector isn't a "good" reflector.

I spent several years working for NASA, right out of college, where I learned to be a research engineer. All of the techniques I use I learned there, from other much more experienced research engineers.

I would very much like for someone like you to use your skills and knowledge to try to further improve our understanding of how to select an appropriate light for any planted aquarium. I can think of other ways to approach this even now, and when I run out of other things I want to do, I will likely pursue one or more of those approaches to see if that works better.

EDIT: I'm always forgetting to play the age card. What makes my results unassailable is that I am 75 years old, therefore infallible.:icon_mrgr


----------



## shortsboy

Hoppy, you never cease to make me smile, and I certainly hold you to be sufficiently unassailable.


----------



## Higher Thinking

Do your thing Hoppy! Way to go!


----------



## plantbrain

jonathandowers said:


> Ok, I'm going to go against the grain and say this experiment is dubious, and needs extensive clarification.


Even a typical uneducated hobbyists like myself seems to find them pretty easy to read.......



> Why aren't the types of reflectors and specific models listed? What defines a "poor" reflector?


In some cases this information is simply not available as to brand of reflector, but they could be added, but this can make the charts a lot more messy. Any distillation of information will sacrifice some data in order to simplify.
Do we need such rigor? What is the goal?

We are simply trying to improve on the old method of Watt/gallon, which this has done very well and Hoppy has put the effort into creating and measuring out. Perfection? Never, better and closer to perfection? A little bit. Certainly better than the old alternative.



> While the results presentation looks pretty, the procedures are undocumented and rather hand wavvy (no, I'm not talking about t-values either).


Why not ask Hoppy directly about the methods? Be a "guide" to improve the methods since you have such awesome creds, no? You have not done that but had enough gumption to post. Offer up some good methods then. 



> I have worked as a researcher at several prestigious labs. So I do have higher standards when reading and analyzing results.


What does this have to do with screaming howler monkeys flying out my rear?
Why would you inject this steer manure into this? 

If you are this good, then why have you not done your own table and testing? Why have you not offered a better set of methods? You need to offer more than mere complaints...you need to offer solutions to the problems and issues you have with the table and methods.



> Taken alone, these results do not make sense to me.


Taken alone, I find little issue with the chart, it can be off, as can any model ..........that distills and generalizes data. 300-400$ light meter vs the chart? Most hobbyist will go for the chart. The Meter is a back up and used often in clubs for more specific precise examples, test etc. I adjust my intensity and do a fair amount of set ups and can rationalize the meter for myself. But if Hoppy wants to knock himself out with it and make these charts, I ain't got no beef with it. Better him than me I say:thumbsup: If he's got a question or wants some input, he'll ask, or pose a question of an unexpected result. If I see something wrong, I'll say why and what might be a better method to answer that question......and the trade offs as far as a hobbyist may face trying to get that data/measurement etc.


----------



## audioaficionado

Hoppy said:


>


I found this forum from a link on Bob's Tropical Plants and this thread and graph convinced me that this was the place for me.

Correct me if I'm off, but is a T5HO lamp roughly twice as effective as two T5NO lamps for a 20" deep tank?

I have a DIY redwood hood with 4x5TNO based fixture I built from two F21T5 twin lamp fixtures I got in the local plumbing and lighting home improvement store. No polished reflectors (yet). It used to house two F30T12/CW lamps for several years until the ballasts melted.

Thanx again for this friendly and knowledgeable forum. :thumbsup:


----------



## houseofcards

Putting emotion aside. The real question here for me anyway is not whether the data has value (of course it does), but rather in the way people use it. 

Simple example question:

Over the same tank, does someone end up with a different light intensity setup (low, mid, high) using a *Nova Extreme * T5HO fixture vs a *Tek* T5HO fixture with the same configuration of bulbs?


----------



## Hoppy

audioaficionado said:


> I found this forum from a link on Bob's Tropical Plants and this thread and graph convinced me that this was the place for me.
> 
> Correct me if I'm off, but is a T5HO lamp roughly twice as effective as two T5NO lamps for a 20" deep tank?
> 
> I have a DIY redwood hood with 4x5TNO based fixture I built from two F21T5 twin lamp fixtures I got in the local plumbing and lighting home improvement store. No polished reflectors (yet). It used to house two F30T12/CW lamps for several years until the ballasts melted.
> 
> Thanx again for this friendly and knowledgeable forum. :thumbsup:


The problem with T5NO lights is that there are so few of them. Almost all T5NO lights have been the Coralife ones, which have very poor reflectors. Recently some PAR readings were made with those lights, by others here, notably DaveH. They were disappointingly low. Unless you use T5HO reflectors, 2 T5NO bulbs are not nearly equal to one T5HO bulb. Instead, they are about the same as T8 bulbs. When you stop and think about it, knowing that good reflectors can increase the PAR from T5HO bulbs by nearly 3X, it makes sense that good reflectors are the main reason for the brightness of T5HO lights, and the absence of good reflectors is why T5NO lights tend to be disappointing.

However, we also know now that you don't need nearly as much light as we used to believe in order to grow plants very well. With good CO2 you can grow plants well, but slowly, using far less light. So, T5NO lights can be very useful, and have always been so for people who do non-CO2, low light tanks.


----------



## Hoppy

houseofcards said:


> Putting emotion aside. The real question here for me anyway is not whether the data has value (of course it does), but rather in the way people use it.
> 
> Simple example question:
> 
> Over the same tank, does someone end up with a different light intensity setup (low, mid, high) using a *Nova Extreme * T5HO fixture vs a *Tek* T5HO fixture with the same configuration of bulbs?


Of course, the answer is that you get much more light with the Tek fixture than with the Nova Extreme, which doesn't have good reflectors.


----------



## Jim Miller

@Hoppy 

Since you and Catalina are in the same city why not drop by with a PAR meter and measure his fixtures. His T5HO fixtures use ballasts which work fine to drive NO bulbs at proper levels.

I'm sure Jim would be glad to do so.

Just a thought

jim


----------



## audioaficionado

I can fit up to six T5NO lamps in my DIY hood. How many T5HO lamps would that be equivalent to? I'm trying to scale so I can see how it would work in your chart.

On the other hand if I could find good two T5HO lamp fixtures with good reflectors that would fit in my 5.5"x36" hood, that would be better in the long run for my 36x12x20 tank.


----------



## jgmbosnia1

WOW.....I never thought people would get so up in arms over this matter. Hoppy has done a great job trying to help out the hobby by giving up his free time to give this forum a great tool to ESTIMATE what type of lighting we will need over our pride and joys. The bottom line is if this chart doesn't work for you then try something else! If you want to try raising your light 2' from the top of the tank....cool. If you want to try 1" from the top....go for it. IMO this will never be an exact science.....it's close.....but not exact.

If you think you have something of *value* to offer this forum then please do.

Thanks again Hoppy!


----------



## plantbrain

Jim Miller said:


> @Hoppy
> 
> Since you and Catalina are in the same city why not drop by with a PAR meter and measure his fixtures. His T5HO fixtures use ballasts which work fine to drive NO bulbs at proper levels.
> 
> I'm sure Jim would be glad to do so.
> 
> Just a thought
> 
> jim


I already loaned him the PAR meter, but they have not said much to me since. He's got work and employees to deal with, so it could be awhile.


----------



## plantbrain

jgmbosnia1 said:


> WOW.....I never thought people would get so up in arms over this matter. Hoppy has done a great job trying to help out the hobby by giving up his free time to give this forum a great tool to ESTIMATE what type of lighting we will need over our pride and joys. The bottom line is if this chart doesn't work for you then try something else! If you want to try raising your light 2' from the top of the tank....cool. If you want to try 1" from the top....go for it. IMO this will never be an exact science.....it's close.....but not exact.
> 
> If you think you have something of *value* to offer this forum then please do.
> 
> Thanks again Hoppy!


There'd be no hobby if it was all about +/- 5% ppm or umol.

Many have attempted to argue and bemoan that it is required, only to be falsified time and time again in abject failure.
Then the "back tracking" begins.

Rather than taking that approach, a good question is much wiser and more instructive. Over what range(max/average mid/min) can aquarist grow plant species X,Y, and Z of umol of light?

How does depth influence this with X, Y, and Z brands/light configurations?

These are questions that aquarist can do and answer that applies to their needs. No, not everyone will be able to grow say _Syg "belem"_ at 30 micromols, but all it takes is one person to provide a nice example of this to lower the effective min lighting requirement.

Same with another species etc.......we know some of the upper ranges are going to be in the 400-600umol ranges.........which few except a few Reef folks might have.

While 30 might work if the nutrients and the CO2 are optimal, we will want to add some wiggle room for these NOT being the best all the time, so instead of 30, we suggest say 40-50 umol.

No need to be on the razor's edge, same for CO2, same for nutrients for that matter.


----------



## shortsboy

audioaficionado said:


> I can fit up to six T5NO lamps in my DIY hood. How many T5HO lamps would that be equivalent to? I'm trying to scale so I can see how it would work in your chart.
> 
> On the other hand if I could find good two T5HO lamp fixtures with good reflectors that would fit in my 5.5"x36" hood, that would be better in the long run for my 36x12x20 tank.


I've got the Coralife 2xt5ho 4" above the same size tank and it produces absolutely huge amounts of light (no quantitation, but I had to keep co2 at near-gasping fish levels to keep up with that light if it was any lower), and that's with middle of the road bulbs. If you want as much or more 5depending on How high you'd mount, using Giessman bulbs or a Catalina 2xt5ho should do everything you need and more.


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## houseofcards

Hoppy said:


> Of course, the answer is that you get much more light with the Tek fixture than with the Nova Extreme, which doesn't have good reflectors.


If the answer is that it's much more light then it would be tough IMO to rely on the graph for whether your in a low to high light situation simply based on type of fixture. If we are talking 5 - 10% difference than that's another story.

I understand we are trying to keep thing's simple, but it might not be possible. The coralife 2x24 fixture looks to be almost identical to the nova extreme one. These are two big players in this space.


----------



## Hoppy

Coralife fixtures, the ones I have seen or seen photos of, don't have good reflectors. I get the impression that the designer of those lights considered the reflector to be a beauty item, not a functional one. The Nova Extreme appears to have been designed by he same person.

If I felt the charts were not usable I wouldn't use them. If you feel that way, you shouldn't use them either. It isn't mandatory. Let us know how you make your lighting decisions, because we can use some alternatives.


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## audioaficionado

A H Supply 49634 - MIRO 4 Reflector for one 96 watt compact
34.5"L x 4"W x 2"H.
Price: $19.99

Might work with my T5NO lamps/fixtures. Worth a gamble for only $20 ea.

I don't want to derail the purpose of this excellent thread, but I've found you can make things as complicated as you want. However you don't always get a good return on your time investment if you choose to do so. I like the simplicity of Hoppy's concept.


----------



## macclellan

audioaficionado said:


> A H Supply 49634 - MIRO 4 Reflector for one 96 watt compact
> 34.5"L x 4"W x 2"H.
> Price: $19.99
> 
> Might work with my T5NO lamps/fixtures. Worth a gamble for only $20 ea.


You should buy a T5 reflector, not a CF reflector, for a T5 bulb. The price is the same or less. Bulk Reef Supply has the Tek II Retrofit Reflector (a very good reflector) for $19.99.


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## audioaficionado

macclellan said:


> You should buy a T5 reflector, not a CF reflector, for a T5 bulb. The price is the same or less. Bulk Reef Supply has the Tek II Retrofit Reflector (a very good reflector) for $19.99.


You're right. Thanx for that tip :thumbsup:


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## Buc_Nasty

Anyone seen this? Marineland par values for their LED fixtures. Who knows if they're accurate or not but its at least PAR data. The 36" model can be gotten for $93 shipped. Only 23.5 watts too

http://www.marineland.com/uploadedFiles/Marineland/11078iMLLEDCharts.pdf


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## Dave-H

That highest power one seems pretty good, actually. I wonder if it really produces that much light. I'm a bit skeptical.

The reef capable/triple one seems to have lots of PAR. What happens if you put this over a freshwater planted aquarium? I assume that the PAR would still support the plants as if it were a more desirable frequency, but it would look different?


----------



## Buc_Nasty

The high power "reef capable" ones have almost all 10,000K white LED's and a few actinic blue LEDs so they wouldnt do well for a planted tank

but the "double bright" ones have 6000k white and 60mw "blue" LED's in a 2:1 ratio. It says be "low light" on most tanks though.

You can see some videos on youtube of them...not bright but I like the look. I might go for that 36-inch LED fixture on my 65 gallon.


----------



## Dave-H

The spread is awful, it appears. At least according to this chart on another forum.


----------



## Buc_Nasty

could u post a link to the chart you're talking about?


----------



## Dave-H

http://www.3reef.com/forums/reef-lighting/marineland-gets-reef-capable-new-led-lamps-94568.html


----------



## Buc_Nasty

By spread do you mean spread over the light spectrum? B/c those graphs were for the reef model which is different than the double bright model


----------



## Dave-H

Sorry about that broken link 

What I meant is: the spread of the light, i.e. how wide of an area is illuminated beneath the light. If the chart on that forum post it correct (although I'm not sure I understand what the source is) then at 24 inches the light doesn't even spread out beyond the width of the fixture! To get that maximum PAR you have to literally be right under the light. It seems hard to make that work. Am I understanding this correctly?


----------



## Buc_Nasty

Oh. I cant seem to find a chart for spread on that forum u posted...

I think I'm going to buy 2 of the 36-48" double brights at petco and test them out on my tank then return them. If I like them I'll buy them online for $80 cheaper haha

I'll post some pictures/findings. Unfortunately I don't have a PAR meter or access to one.


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## Dave-H

Sorry, try here: http://glassbox-design.com/2010/marineland-reef-capable-led-light/


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## Steve001

Hoppy said:


> I got those light ranges from Tom Barr, but several months after that thread you referenced. I think we were all struggling to figure out what PAR values meant at that time. And, I believe it was later that Tom measured the ADA tanks at Aquaforest in SF and found just how low the light levels in typical Amano tanks were.  He also began reducing his own light levels quite a bit after that, so I assume it was that experience that led to the ranges he suggested.



I'm a little late to this. can you provide a link which will lead me to a talk about that which is underlined ?


----------



## audioaficionado

Thanx to this thread, I've figured out and found my economical lighting solution for my 40gal tall tank.
Sun Blaster T5 HO Fluorescent Strip Lights


----------



## Buc_Nasty

You realize that the T5HO line on the graph applies to bulbs with individual reflectors right? The ones you linked to won't provide nearly as much light as the T5HO line on the graph. Just makin sure you realize that when planning your tank.


----------



## audioaficionado

Buc_Nasty said:


> You realize that the T5HO line on the graph applies to bulbs with individual reflectors right? The ones you linked to won't provide nearly as much light as the T5HO line on the graph. Just makin sure you realize that when planning your tank.


I'm planning on getting snap on reflectors for them from the same place. Hopefully the local dealer has some in stock so I can have some instant gratification :icon_mrgr


----------



## feh

Does this chart mean the actual tank height or from the substrate?


----------



## Hoppy

feh said:


> Does this chart mean the actual tank height or from the substrate?


It means the distance between the light source and where the PAR reading is taken. If you assume most bulbs are 2 inches from the front of the light, and most substrate is 2 inches deep, it translates to tank height. But, the chart is not so accurate that it makes any real difference.

And, yes the T5HO line is meant to be for lights with individual reflectors for each bulb, which was the norm when I started making the chart. Time marches on!


----------



## feh

What kind of spacing would you suggest on a 75? One in the front maybe about an inch or two from the glass and same for the rear or closer together?



plantbrain said:


> http://www.ahsupply.com/54wInstalls.htm
> 
> For folks with wood type hoods, this 2 bulb configuration is all you might ever need for most tanks up to 75Gal.
> 
> Certainly not more.
> Ideally, you'd be able to have each bulb on a timer.
> 
> Even 1x 54 W on a 55 gallon tank is enough to grow most plants.
> 
> I use 2x 24 w at 1 meter distance from the sediment bottom and am getting 30-35 micromols.
> 
> 20-25 are the lower limits for many species.
> 40-50 is optimal for most
> 
> Regards,
> Tom Barr


----------



## nsgrkg

*all this info confuses me....*

I am very much a novice of the planted tank, and the more I read about lighting, the more confused I get (not really...starting to sink in but lot of differing info out there). I have a 54 gallon bowfront with Nova Extreme T5HO 2x24 with single reflector on top of tank. From reading Hoppy's chart it looks like my lighting falls into the high range....but from what I have read here on the more recent posts, with a single reflector I would fall into medium light range? I have the original bulbs that came with the setup, one 10,000K daylight and a pink plant growth lamp.


----------



## Hoppy

nsgrkg said:


> I am very much a novice of the planted tank, and the more I read about lighting, the more confused I get (not really...starting to sink in but lot of differing info out there). I have a 54 gallon bowfront with Nova Extreme T5HO 2x24 with single reflector on top of tank. From reading Hoppy's chart it looks like my lighting falls into the high range....but from what I have read here on the more recent posts, with a single reflector I would fall into medium light range? I have the original bulbs that came with the setup, one 10,000K daylight and a pink plant growth lamp.


Not all T5HO lights are equal, and the Nova Extreme is one of the less equal of those available. I know it doesn't fit the chart, but I'm not sure where it does fit. If I were to guess I would guess that it gives from half to 2/3 the light that the chart indicates.


The other question about locating two lights above a 75 gallon tank: I would put them about 8-10 inches apart. I'm basing this on some data I got from a light that had an empty MH area in between two rows of T5HO bulbs. The PAR was not 4X one T5HO, but closer to 2X one T5HO. So, a separation of about 6 inches seems to be enough to keep the light from the two sets of bulbs from adding together. 8-10 inches just gives some more cushion, and spreads the light out more.


----------



## fauxjargon

Hoppy said:


> Not all T5HO lights are equal, and the Nova Extreme is one of the less equal of those available. I know it doesn't fit the chart, but I'm not sure where it does fit. If I were to guess I would guess that it gives from half to 2/3 the light that the chart indicates.
> 
> 
> The other question about locating two lights above a 75 gallon tank: I would put them about 8-10 inches apart. I'm basing this on some data I got from a light that had an empty MH area in between two rows of T5HO bulbs. The PAR was not 4X one T5HO, but closer to 2X one T5HO. So, a separation of about 6 inches seems to be enough to keep the light from the two sets of bulbs from adding together. 8-10 inches just gives some more cushion, and spreads the light out more.


The Nova Extreme / Corallife fixtures are huge wastes of energy and money. The Hagen Glo fixtures are better but not by much. This is based entirely on experience with no values to back it up. OTOH, at work we have plants growing nicely in a low tech 15 gallon with nothing but a Marineland Double Bright LED strip on it. They're a good option for a non-diy high-efficiency, shallow low tech tank.


----------



## nsgrkg

so....now that i know i have an inferior fixture....can i improve on it with better bulbs? i can't do much about bulb placement b/c tank corner bowfront, can't suspend lights because of glare in relation to setup of room and comfort. i need to make what i have work. suggestions?


----------



## Dave-H

nsgrkg said:


> so....now that i know i have an inferior fixture....can i improve on it with better bulbs? i can't do much about bulb placement b/c tank corner bowfront, can't suspend lights because of glare in relation to setup of room and comfort. i need to make what i have work. suggestions?


That is my challenge with my 54 gallon corner bowfront - hard to light. I have found a few combinations that work well but it's not easy. Hard to get good circulation, too.


----------



## houseofcards

fauxjargon said:


> The Nova Extreme / Corallife fixtures are huge wastes of energy and money. The Hagen Glo fixtures are better but not by much. This is based entirely on experience with no values to back it up. OTOH, at work we have plants growing nicely in a low tech 15 gallon with nothing but a Marineland Double Bright LED strip on it. They're a good option for a non-diy high-efficiency, shallow low tech tank.


I don't know if it's a huge waste of money. Depending on your tank size, plants and what your trying to do there is nothing wrong with the lights. I have both the current and nova 2x24 lights and they are very similar in output. Keeping it real these two brands are more reflective (no pun) of what these lights are like in the category. Along with Hagen, Zoo-med and a few other brands they would clearly make up the majority of t5ho lights used.


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## DKRST

houseofcards said:


> I don't know if it's a huge waste of money. Depending on your tank size, plants and what your trying to do there is nothing wrong with the lights. I have both the current and nova 2x24 lights and they are very similar in output. Keeping it real these two brands are more reflective (no pun) of what these lights are like in the category. Along with Hagen, Zoo-med and a few other brands they would clearly make up the majority of t5ho lights used.


I concur. I'd love a "better" light, but my 36" Zoo-med AquaSun T5HO was what I could afford & easily purchase locally. It's more light than I need with both bulbs on (low-tech tank). I would love to see some of the lower-cost T5HO's fixtures tested (in a single bulb and dual bulb configuration) and then graphed on Hoppy's chart to see how they compare with higher-end setups!


----------



## tom855

I have used the Nova Extreme for years, and although they may not be the best, I've found out (with this thread and the purchase of a PAR meter), that I had way too much light even WITH the "inferior" fixtures. They may not be the best but they are way more than I needed. They will do fine for you.


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## patola

I wanted to get some advice if i could, right now i have a 30 gallon tank, 14 inches to the substrate, and i have a single t5HO tube with a really good reflector, its 39 watts, 36 inches long, is only 3 inches away from the surface of the water and im having trouble figuring out what light range i'm in....i also have a single t8 tube, but i don't use it, but can if i need too. Any suggestions?


----------



## audioaficionado

What type of lighting is the old rule of thumb W/gal based on?

My two T5HO 39W lamps w/reflectors are 2W/gal over my 40gal tank, but I'm pretty sure they are a lot brighter than 80W of T8/12 tubes.


----------



## Hoppy

audioaficionado said:


> What type of lighting is the old rule of thumb W/gal based on?
> 
> My two T5HO 39W lamps w/reflectors are 2W/gal over my 40gal tank, but I'm pretty sure they are a lot brighter than 80W of T8/12 tubes.


The "watts per gallon" "rule" was for T12 lights on a tank with standard dimensions, not a "high" tank, nor a "long" tank, nor a "breeder" tank. It was only a coincidence that the "rule" worked at all.



patola said:


> I wanted to get some advice if i could, right now i have a 30 gallon tank, 14 inches to the substrate, and i have a single t5HO tube with a really good reflector, its 39 watts, 36 inches long, is only 3 inches away from the surface of the water and im having trouble figuring out what light range i'm in....i also have a single t8 tube, but i don't use it, but can if i need too. Any suggestions?


You have high light, and you would have a much more enjoyable time with the hobby if you raised that light to about 22 inches from the substrate.


----------



## patola

> You have high light, and you would have a much more enjoyable time with the hobby if you raised that light to about 22 inches from the substrate.


Why? im pretty sure with a little work i can get it to 22 inches, but what is the purpose?


----------



## audioaficionado

patola said:


> Why? im pretty sure with a little work i can get it to 22 inches, but what is the purpose?


Algae (the lack there of).


----------



## patola

oh, so let me see if i understand this correctly, my lights are too close to the tank, which is too high of light, which in time could cause an algae outbreak? Also, i know this may be hard to answer without other information, but with the info i have provided, do you think i need a co2 system? i don't have one but am not sure if i need one. thanks for all the help!


----------



## Mxx

So now that we have somewhat a standard to work with for florescent lights, can someone do the same thing for LED lights??? 

And being that LED's each seem to follow a very similar spectral distribution regardless of manufacturer, might it be possible to formulate an equation or chart which (through measured results of each), could be used to determine a Lux/PAR equivalence? In that way we could each use much cheaper Lux meters instad of having to use expensive PAR meters to measure our lighting levels. 

Yes, it's not perhaps 100% precise, but potentially still could be sufficient to help most aquarists. One LED variable that would need to be measured in turn are the different LED temperatures, i.e. cool white/natural white/warm white. Would that not be a reasonable approach and of benefit?


----------



## IWANNAGOFAST

I think it's too hard to do an LED graph, PAR is affected by the spacing too. Too many variables w/ the DIY fixtures.


----------



## Hoppy

LED results depend on whether optics are used, what current they run at, how many per square foot of footprint are used, how far from the substrate, and what model LED (XP-G, XM-L, etc.) It would be very hard to make a chart that would be useful.

However, one idea that might work is to start with lumens. LEDs are unique in that nearly 100% of the lumens produced can be directed into the tank. You can't do that with fluorescent or MH lights. So, with a lot more effort I believe you could arrive at a lumens per square foot of substrate surface that would correlate well with PAR. And, nearly all LEDs are rated for some number of lumens at 350 mAmps.

Some day I hope to work on this, but I would be happy to have someone beat me to it.


----------



## extrame

anybody use energy saving bulbs like this? 
http://www.philips.com.ph/c/energy-...D08EAE505B98ADD3.app101-drp3?t=specifications

hope you guys could add this kind of bulbs in your graphs


----------



## Mxx

Yes, those things are true, and it's unfortunate that even LEDs themselves are not sold with detailed information in regards to how many lumen they produce at different currents. If we had a little more information on this we could at least arrive at some conclusions of how many lumen per square foot we're achieving. 

I did see that someone was testing and graphing LED output at a few different currents, though they didn't provide total figures in terms of either lumen or PAR.

But what about the second part of that question, which is the critical question of whether we can determine a lumen/PAR equivalency? If someone could determine that then we could each use $17 lumen meters, instead of PAR meters costing at least ten times that. For more-or-less, regardless of LED brand, current, optics, distance, and possibly even color temperature, the spectral output and therefore lumen/PAR ratio should remain consistent, so that would be a relatively easy thing to determine thereafter. And then we could each use cheap lumen meters to dial our drivers to the correct current to achieve the PAR levels we're targeting, no? 

One caveat there is that the inexpensive lumen meters are not waterproof, so you'd have to measure the light output at substrate level prior to filling the tank. And light will react slightly differently in a tank filled with water than in any empty tank. A measurement could be taken as well halfway to the substrate, which would be easy enough to test against later on during a water change to determine later if the light output has shifted in time though. But if the initial tests measure dry lumen versus wet PAR then that should potentially solve that problem.


----------



## Hoppy

Cree does a good job of providing data for their LEDs. They tell you the lumens output at 350 mAmps, for most of them, and give you a chart showing the change in lumens vs current. With that you can easily calculate a usable number for lumens vs current. Since the relationship between PAR and Lux depends on the spectrum for LEDs, or any other light, I don't believe there will ever be a good conversion factor that we can use. However, once we test some typical LEDs, like cool white and warm white, we can get a usable conversion factor, assuming we use a design that gets all of the LED light into the tank. Once I get data on the LED light I'm working on now (or would be if I had the LEDs) I think I can use that, plus data from the two lights I already have, each with different model LEDs, to come up with something useful. It seems interesting enough that I will enjoy doing it.


----------



## Mxx

Well I applaud you if you're up for testing your LED Lumen versus PAR as such, certainly as I don't myself have the facilities to undertake this. To me personally (as I assume is the case for many others), there are two aspects of this which would be very beneficial. 

The first would be in designing the lighting system for a new tank, and thus determining the Lux I'd be aiming for to achieve say a medium PAR intensity. I previously hadn't seen a lumen/current chart for CREEs, but with the benefit of that and a reasonable conversion factor the resultant desired lumen design value should be an easy thing to calculate. 

And secondly, once the LED rig is built and in place, I could at that point use a lumen meter to confirm the light intensity and dial the drivers in as necessary to achieve a relatively close approximation of my desired PAR value, without having to fork out unnecessarily for a PAR meter. 

I'm planning to have a big tank to work with, so I was thinking of using three interwoven strings of neutral white, warm white, and cool white, each on separate dimmable drivers so that I could adjust the colour temperature to precisely what happens to look the most appealing.


----------



## audioaficionado

My plans are massive overkill and then dim the LEDs as needed. :biggrin:


----------



## Uptown193

Can someone tell me if a 20" Coralife Freshwater Aqualight Series - Single Linear Strip with 96 watt 6,700K "Quad" Compact fluorescent Lamp be good enough for a 10 gallon planted tank, some red plants as well in tank??? Please.


----------



## Hoppy

I believe it will give you medium light. Coralife PC fixtures seem to all have poor reflectors.


----------



## xmas_one

Hoppy said:


> I believe it will give you medium light. Coralife PC fixtures seem to all have poor reflectors.


I'd say it would be a lot more than medium light. Even with no reflector, those quads are super bright..


----------



## houseofcards

Hoppy said:


> I believe it will give you medium light. Coralife PC fixtures seem to all have poor reflectors.


Compared to what? Tek and AH supply. The majority of fixtures on the market are more similar to Coralife.


----------



## houseofcards

xmas_one said:


> I'd say it would be a lot more than medium light. Even with no reflector, those quads are super bright..


Let's put it this way, on a 10g that light will grow anything you want, including algae if your not on your game.


----------



## RickRS

extrame said:


> anybody use energy saving bulbs like this?
> http://www.philips.com.ph/c/energy-...D08EAE505B98ADD3.app101-drp3?t=specifications
> 
> hope you guys could add this kind of bulbs in your graphs


That's just a spiral CFL packaged in a PAR38 bulb shape. You want to check out the "Power Saver" sticky for spiral CFL info.


----------



## Uptown193

Hoppy said:


> I believe it will give you medium light. Coralife PC fixtures seem to all have poor reflectors.


Wow, really, only medium light. 96W intensity in a 10g, I am shocked.

Actually I ended up ordering a 24" SILVER SOLAR T5 HO AQUARIUM LIGHT FIXTURE from Catalina Aquarium but with 2 x 24W 6500K bulbs. Oh and with German reflectors, if that means anything. What are your opinions on this for a heavily planted tank with some red plants as well? http://www.catalinaaquarium.com/store/product_info.php?cPath=71_136&products_id=1410

Rich


----------



## Hoppy

houseofcards said:


> Let's put it this way, on a 10g that light will grow anything you want, including algae if your not on your game.


Until someone actually uses a PAR meter to measure the output, we can only guess. I'm thinking now that it may do better than I thought, with 4 parallel tubes instead of just two. But, without any data, it can only be a guess. No question, it is plenty of light for a 10 gallon tank in any case.



Uptown193 said:


> Wow, really, only medium light. 96W intensity in a 10g, I am shocked.
> 
> Actually I ended up ordering a 24" SILVER SOLAR T5 HO AQUARIUM LIGHT FIXTURE from Catalina Aquarium but with 2 x 24W 6500K bulbs. Oh and with German reflectors, if that means anything. What are your opinions on this for a heavily planted tank with some red plants as well? http://www.catalinaaquarium.com/store/product_info.php?cPath=71_136&products_id=1410
> 
> Rich


That one is almost certainly going to be much too much light unless it is suspended about a foot above the top of a typical 10 gallon tank. And, it is going to spill a lot of light to light up the walls, floor, etc. If you put several layers of window screen over it you can "tame" it enough for 10 gallon use sitting on the tank.


----------



## houseofcards

Hoppy said:


> Until someone actually uses a PAR meter to measure the output, we can only guess. I'm thinking now that it may do better than I thought, with 4 parallel tubes instead of just two. But, without any data, it can only be a guess. No question, it is plenty of light for a 10 gallon tank in any case..


This is one of the reasons I think it's hard if not impossible to graph this stuff. There are too many variables influencing the amount of light that is reaching the plants. You have quad bulbs, reflectors, bulb shape, etc. You might be right about the PAR reading, but let's face, I'm seeing ridiculous swings in PAR readings for the same fixtures. I can look at my tanks and see what it's doing with certain lights and know how strong the light is. I'd go by that over a PAR reading. I'm not totally comfortable anyway with what is considered an acceptable PAR reading for plants to grow to their fullest. You really have to go with experience IMO. 

That Catalina 2x24 fixture that was linked states "..has its own individual German polished aluminum reflector that *TRIPLES* the light output into your aquarium from each bulb". If that's definitely accurate), but how do you throw that into the mix."


----------



## Uptown193

houseofcards said:


> That Catalina 2x24 fixture that was linked states "..has its own individual German polished aluminum reflector that *TRIPLES* the light output into your aquarium from each bulb". If that's definitely accurate), but how do you throw that into the mix."


Can reflectors do that and are reflectors that important and/or depended upon when it come to lighting?


----------



## Hoppy

Uptown193 said:


> Can reflectors do that and are reflectors that important and/or depended upon when it come to lighting?


You can easily verify this. Just look up at the bulb and note whether you can see 3 whole bulbs, instead of one. The two extras are from the reflector, and a good reflector gives you 90+% of the intensity as the light from the real bulb. That means almost tripling the amount of light getting into the tank. Some reflectors even give you more than 2 reflected images of the bulb, so you might get a bit more light from them.

No one can dispute that experience is a better way to pick the right light for your tank. But, few of us have the wide experience to be able to do that. Are we supposed to buy 3-4 lights from the LFS, take them home and try all of them, then return the ones that aren't what our experience says we need? How about new light designs - LED lights for example - none of us have wide experience with these yet? Do we just refuse to use them for that reason? We all need a way to make a decision on what lighting is most likely to give us the amount of light we need - that is all a chart like these can ever do.


----------



## aquaman4fish

Hoppy,
I still don't understand. If I want a non CO2 diffuser tank, I should have what type of lighting? Low, medium, or high? 
Thank you!


----------



## Hoppy

If you want a non-CO2 tank you can't use medium or higher light without very likely running into algae problems. You need low light. But, having low light doesn't mean you shouldn't use CO2. With low light and CO2 you can grow almost all of the plants in the hobby. Low light without CO2 restricts you to "low light" plants.

The point to remember, if you decide you want to grow "high light plants", you will have made the decision to buy a good CO2 system. So, since you have the CO2 system, you can gain a lot by using low medium light and the CO2 system instead of high light and the CO2 system. This means you never really need high light, so why use it?


----------



## aquaman4fish

Is it okay to have medium light with 2 bulbs T5NO for a 21" high low tech tank?
Or, do you recommend something else?
Thank you Hoppy!


----------



## audioaficionado

aquaman4fish said:


> Is it okay to have medium light with 2 bulbs T5NO for a 21" high low tech tank?
> Or, do you recommend something else?
> Thank you Hoppy!


T5NO lights shouldn't be any brighter than a T8/T12 shop light fixture. It sounds like low light. That's what I had before I upgraded to T5HO fixtures on my 24" tall tank.


----------



## houseofcards

Hoppy said:


> ...Are we supposed to buy 3-4 lights from the LFS, take them home and try all of them, then return the ones that aren't what our experience says..


Uh, your suppose to read the forum, LOL. That is what the forum is mainly for, to share ones experience with products, plants, etc. The forum is wide and far reaching. The fact that you state a reflector 'can' make a light 3x stronger makes a chart by light type alone difficult to use. 


Sent from my iPhone using Tapatalk


----------



## aquaman4fish

Thanks audioaficionado!


----------



## Uptown193

Hoppy said:


> You can easily verify this. Just look up at the bulb and note whether you can see 3 whole bulbs, instead of one. The two extras are from the reflector, and a good reflector gives you 90+% of the intensity as the light from the real bulb. That means almost tripling the amount of light getting into the tank. Some reflectors even give you more than 2 reflected images of the bulb, so you might get a bit more light from them.
> 
> No one can dispute that experience is a better way to pick the right light for your tank. But, few of us have the wide experience to be able to do that. Are we supposed to buy 3-4 lights from the LFS, take them home and try all of them, then return the ones that aren't what our experience says we need? How about new light designs - LED lights for example - none of us have wide experience with these yet? Do we just refuse to use them for that reason? We all need a way to make a decision on what lighting is most likely to give us the amount of light we need - that is all a chart like these can ever do.


So the Catalina 2x24" T5HO on a heavily planted 10g with 6700K bulbs might be a lil took much staying on 8 hours a day?

Does anyone suggest a UV sterilizer?


----------



## Hoppy

Uptown193 said:


> So the Catalina 2x24" T5HO on a heavily planted 10g with 6700K bulbs might be a lil took much staying on 8 hours a day?
> 
> Does anyone suggest a UV sterilizer?


Any T5HO light is a poor choice for a 10 gallon tank. If you raise it enough to get the light intensity down to a reasonable value, you light up the whole room with spilled light.


----------



## Uptown193

Hoppy said:


> Any T5HO light is a poor choice for a 10 gallon tank. If you raise it enough to get the light intensity down to a reasonable value, you light up the whole room with spilled light.


I guess I will be upgrading to a bigger tank sooner then later


----------



## BlueJack

Hoppy said:


> Originally Posted by Oreo
> What's the conversion factor from LUX to PAR? I understand it would't be exact because of what PAR and LUX are and that different bulbs perform differently throughout the spectrum. Still, it would be useful information to have a ball-park idea of how the two compare from an average bulb.
> 
> I haven't tried to determine the answer to that. Most bulb manufacturers don't print the LUX @ X inches rating on their bulb packages, so I never felt it was an important thing to know. I do know that the conversion factor would be much different for a GE9325K bulb, a 6500K cool white bulb, a 10,000K bulb, etc. How much different I don't know either. Someone else can have the fun of figuring this out:smile:
> 
> T5NO lights are interesting. I read a few years ago that the efficiency for converting watts to light for a T5NO bulb is higher than for a T5HO bulb. And, I know that for any given length bulb, T5NO bulbs are a little more than half the wattage of T5HO bulbs. From that you could assume that a 2 bulb fixture with T5NO bulbs would produce about the same or a little more PAR than a one bulb T5HO fixture. *Except*, that few T5NO fixtures use reflectors that are nearly as good as typical T5HO fixtures. And, the reflector accounts for a big percentage of the efficiency of T5 bulbs. Until someone gets several PAR meter reading for a few different T5NO fixtures I don't know how we will ever know how to judge those fixtures.


Thanks for this thread Hoppy! I can directly attribute my tanks success to your research. I don't know if this has been answered yet. On the Lux to Par question:

Each type of lamp (MH HQI, Fluor., Halogen, soda, etc.) produces the same amount of PAR on 1Watt. Since the amount emitted by lamp light in Lux is directly related to its capacity, it is clear that the ratio of PAR-> Lux is also fixed. That is, light metering under the lamp in Lux-PAR can be found simply by multiplying by a certain coefficient. 

Conversion factors PAR -> Lux: Sunlight x54, MH Lamp x71, cool fluorescent x74. 










Inverse coefficients for the transfer of Lux -> PAR, respectively, for the Sun x0.0185, cool fluorescent x0.0135 and MH x0.0141 










Since most of us use Fluorescent lights, here are a few more coefficients for Lux -> Par










With Lux meters running for about $13 on amazon this is a very inexpensive way to measure your lighting. Results from a Lux meter do not vary more than 20% from a PAR meter's results. It's not as exact but nonetheless, gives you a very good idea of your PAR.


----------



## RickRS

BlueJack said:


> Each type of lamp (MH HQI, Fluor., Halogen, soda, etc.) produces the same amount of PAR on 1Watt.


How do you know this? Research?


----------



## BlueJack

RickRS said:


> How do you know this? Research?


Sorry, I should have worded that better. I meant, if you take a specific MH or a specific fluorescent or whatever and run it by 1 watt you will get the same PAR from it every time. From that fixed relationship you can come up with an accurate coefficient for that specific light. That's not to say all MH and florescent's that are run off of 1 watt will have the same PAR. PAR is different from light source to light source. You can see how many different coefficients there are for different kelvin fluorescent bulbs. Using Lux->PAR is really just an estimation anyways. But at such a low entry cost most hobbyist's can put this into practice. It's just adding another piece to the puzzle. Even the PAR meter isn't the end all to lighting measurement. Light sources can have the exact same PAR and have very different spectrum distributions. You need to take both measurements into account.


----------



## Optix

@Hoppy, just kinda curious and have read through about 15 pages

so far, no one has addressed the fact that the light type/distance chart on page1 isnt the same as the chart on page 2

which one is correct?


----------



## Hoppy

Optix said:


> @Hoppy, just kinda curious and have read through about 15 pages
> 
> so far, no one has addressed the fact that the light type/distance chart on page1 isnt the same as the chart on page 2
> 
> which one is correct?


I updated the chart on page 1, so it is the most "correct". This thread has been expanding for so long, some pages are like Newton's law before Einstein started thinking.


----------



## zavikan

Well... Finally finished with all 32 pages of this post...

I can see the 'problem' with using this chart... but only for the uninformed. Perhaps an improvement would be to set up a calculator.

I'll try to make example...using close (by my understanding) multipliers.


Bulb Type at 21"--------- Fixture-----------------# of bulbs-------Glass top

t5ho (16.6)--------Zoomed (x1.5)---------1 (x1)-----------Yes (x.9)
--------------------Tek (x2.9)--------------2 (x2)-------------No (x1)
--------------------Catalina (x2.5)----------3 (x2.5)

This is basicly what I did to figure out my zoomed, and I found some one online already did PAR for the zoomed, and I was dead on.

16.6 x 1.5 x2


----------



## zavikan

BTW if some one makes that, put my name on it someplace would you? dying to see my name in print


----------



## Optix

^^dont be such an glutton for attention ...lol

@Hoppy
why couldnt we model lights based on the relaxation method? its a simplified assumption, but it is accepted in the engineering world and used quite a bit in my realm (ground water engineering). wouldnt it be very, VERY useful in designing an array of LEDs or even a fixture of standard linear bulbs, essentially finding the values and then raising the fixture until the theoretical values converge with the actual? or is that too much of a simplification since we would still have the unknown of the quality of the reflector? just seems like a good, starting point to me...your thoughts?


----------



## Hoppy

When I made that chart I was trying to figure out how to guess at what would be appropriate lighting for a tank. The T5HO data was all taken with lights having good reflectors -the data I had with lights having obviously bad reflectors I just ignored. With more PAR meters in hobbyist's hands, we should be able to gather enough data to find a better way to do this. I don't know what that way will be.

Right now my focus is on LEDs, so this subject gets little of my attention. I really believe that within a few years LED aquarium lights will be as common as T5HO lights are now, and the process of guessing their light intensity is vastly different from that for T5HO lights. I started the ball rolling with these charts, so it's someone else's turn now. Meanwhile, I'm having fun with LEDs!


----------



## magicmagni

Hoppy,

Would you be able to expand this table even further out? Are you able to go out to 6 or even 8 T5HO bulbs and as high as say 24" from top of the tank? Maybe higher if it makes sense to?

thanks


----------



## audioaficionado

magicmagni said:


> Hoppy,
> 
> Would you be able to expand this table even further out? Are you able to go out to 6 or even 8 T5HO bulbs and as high as say 24" from top of the tank? Maybe higher if it makes sense to?
> 
> thanks





Hoppy said:


> ... I started the ball rolling with these charts, so it's someone else's turn now. Meanwhile, I'm having fun with LEDs!


He already answered this :wink:


----------



## magicmagni

audioaficionado said:


> He already answered this :wink:


I must have missed that LOL. This thread is only like 100 pages now ;-)


----------



## HolyAngel

magicmagni said:


> Hoppy,
> 
> Would you be able to expand this table even further out? Are you able to go out to 6 or even 8 T5HO bulbs and as high as say 24" from top of the tank? Maybe higher if it makes sense to?
> 
> thanks


I don't know of anyone who uses/needs more than 4 bulbs, thats crazyness for plants. With good reflectors, you shouldn't ever need more than 2 bulbs unless the tank is over 24" tall and more than 12" wide. 1 bulb per 6" equals good spread across the tank and good lighting unless yeah, you have a really tall tank, at which point you'd do 2 bulbs per ~6". Either way the chart already gets the necessary data for any standard tank you would buy. If it's massive than you adjust accordingly, hope that all makes sense


----------



## audioaficionado

Well I'm contemplating upgrading to a 60"x18"x24" 100 gal tank.

I'm thinking 2 strips of T5HO w/reflectors should still be plenty.

However I might just get by with a few 'Lights of America' deluxe 2xT8x48" shop lights until I get a DIY LED setup built.


----------



## cybercat

This thread just saved me a couple hundred dollars. Thank You so much Hobby.


----------



## Aquaticz

cybercat said:


> This thread just saved me a couple hundred dollars. Thank You so much Hobby.


His name is "Hoppy"
and he is a great asset here


----------



## sevenyearnight

Forgive me if this question has already been asked and answered, :icon_redf but the chart only shows up to 3 T8 bulbs. If over a 20" tank, on top of the tank, would 4 T8 bulbs be medium or still low?


----------



## cybercat

Aquaticz said:


> His name is "Hoppy"
> and he is a great asset here


Opps my bad. I do know someone called Hobby. 

Thank You Hoppy. roud:


----------



## shonick

Hoppy said:


> I have been wondering how much PAR a typical T12 light produces. Like most everyone else I have just assumed that watts per gallon was a way to guess the light from T12 bulbs, but there is no more reason to expect that to mean anything than there is to expect it to mean anything for other bulb types. So, I decided to do some testing.
> 
> I borrowed a new two bulb 48 inch T12 light fixture from one of our local aquatic plant club members, bought a new T12 bulb - a Phillips "Natural Sunshine", 40 watt 5000K, 92 CRI bulb at HD, borrowed our club PAR meter and took some readings. Since I have previously found that I get virtually the same readings with water in the tank and with air in the tank, I omitted the water this time. Then I plotted my smoothed data on a common plot with T5 and PC data:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> To compare this with "watts per gallon", I know that a couple of 2 bulb T12 fixtures will grow plants in a 55 gallon tank. That tank is 20 inches deep, so if the substrate thickness is about the same as the height of the bulbs above the top of the tank, each bulb should give about 9 micromols of PAR, or 36 micromols for 4 bulbs. That is right in the middle of the low light range. So my data is consistent with real life results.
> 
> The light fixture I borrowed has an acrylic splash shield and a removable back, which is a white reflector. I tested the light with and without the splash shield to find that the shield reduces the intensity about 7%. Testing with and without the white "reflector" shows that the reflector increases the intensity by about 36%. The data used for the chart is with both the shield and the reflector.
> 
> Some popular tanks are only 12 inches high. For those tanks T12 bulbs should give about 25 micromols per bulb, so a 2 bulb fixture will give low medium light intensity, probably a good choice for many people with one of those tanks.
> 
> I believe T8 bulbs produce about the same amount of light as T12 bulbs, but at a lower wattage, because they are more efficient. The fixture I borrowed uses starters and magnetic ballasts, so I didn't try it with a T8 bulb.
> 
> EDIT: Updated chart above and added the following chart:
> Another way to use this is to convert it into a simple table, that lets you select a lighting option based on tank height, how high you want the light to be above the top of that tank, and how much light you want. This assumes that multiple bulbs are mounted close together, reflectors are typical for that particular type of light. And, I left out the AH Supply light kits.


did you include the glass cover into consideration for the table?


----------



## Hoppy

shonick said:


> did you include the glass cover into consideration for the table?


No, the loss from a glass top, even a somewhat dirty one is around 15%, which is less than the accuracy of the graph and table. This is just a guide, to get you thinking about the right kind of lighting for a given tank. It is far from being accurate enough to substitute for a PAR meter.


----------



## shonick

Is this T5HO or T5NO?
http://www.petsmart.com/product/index.jsp?productId=11248155
thanks


----------



## 2drtahoe4x4

T5no


----------



## audioaficionado

> Keep your finned friends basking in the glow of the Aqueon T5 Fluorescent 6.7K Lamp. Ideal for freshwater aquariums, the daylight lamp provides a natural white glow, simulating the appearance of sunlight.
> 
> Ideal for freshwater aquariums
> Casts a natural white glow to simulate the appearance of sunlight
> Warranty: 1 year
> 
> Available in *24", 30", 36" and 48"* sizes
> 
> Available in *14W, 18W, 21W and 28W* styles


T5NO values.


----------



## joekidwell

So I have two 36" t5's HO on top of a 20 inch tank with a par of 130 plus 1 30 watt t8 (not sure of the par) that would be considered high light? And the height of you're substrate would improve the light intensity.


----------



## JRMott

Admittedly, I have not read through all 33 pages of this thread though I have searched it.

Here's my question: I currently have 1 x Coralife PC bulb directly above a 16" tank w/ ferts and pressurized CO2. Based on Hoppy's chart, I have medium/low lighting at around 40 PAR. I can run another bulb and effectively double my PAR to just under 80 PAR which would get me medium/high light.

I've read the talk about HLD (high light disease) so now I'm just curious what I stand to gain (or lose) by running both bulbs.


----------



## HolyAngel

JRMott said:


> Admittedly, I have not read through all 33 pages of this thread though I have searched it.
> 
> Here's my question: I currently have 1 x Coralife PC bulb directly above a 16" tank w/ ferts and pressurized CO2. Based on Hoppy's chart, I have medium/low lighting at around 40 PAR. I can run another bulb and effectively double my PAR to just under 80 PAR which would get me medium/high light.
> 
> I've read the talk about HLD (high light disease) so now I'm just curious what I stand to gain (or lose) by running both bulbs.



Basically the only gain is faster growth and increased need for co2 and nutrients, the loss is lots more algea much faster if you ever run out of either co2/nutrients plus increased need to trim the plants


----------



## JRMott

HolyAngel said:


> Basically the only gain is faster growth and increased need for co2 and nutrients, the loss is lots more algea much faster if you ever run out of either co2/nutrients plus increased need to trim the plants


I may have misread the chart a bit, seems I'm likely closer to 25-30 PAR. In any event, I have no desire for very rapid growth, using more co2 and ferts, nor increased algae risks.

My only real concern is that at 25-30 PAR, I've not got enough light for my ludwigia repens, rotala rotundifolia, and my narrow leaf microswords.


----------



## ibmikmaq

T8's give more light then T12's you can not say they give the same light! Every year I start all my garden seedlings in my basement, I built shelves 8 feet by 2 feet three levels each level has 8 two bulb four foot fixtures and my original shelves housed all T12's once T8's became available I built another shelf all housing T8's and I noticed a huge difference in plant growth of seedling compared to the T12 shelf, so much so I got rid of all the T12's and only use T8's! So you can not state T8's give the same amount of light then the T12's because plant growth never lies!


----------



## ibmikmaq

Ok what light fixtures would I need to give med to high light for a tank that is 80 inches long 24 inches deep and 40 inches wide? It's a big acrylic tank!


----------



## JRMott

ibmikmaq said:


> Ok what light fixtures would I need to give med to high light for a tank that is 80 inches long 24 inches deep and 40 inches wide? It's a big acrylic tank!


It's on the chart on the first page.


----------



## plantbrain

JRMott said:


> I may have misread the chart a bit, seems I'm likely closer to 25-30 PAR. In any event, I have no desire for very rapid growth, using more co2 and ferts, nor increased algae risks.
> 
> My only real concern is that at 25-30 PAR, I've not got enough light for my ludwigia repens, rotala rotundifolia, and my narrow leaf microswords.


Well, adjustment without an open top style wire suspension is tougher.......
You can add more, then dial it to about 50 by raising the light.
The problem is that many cannot adjust their lights up or down much if at all.

So getting the sweet spot for PAR is tough. Most all ADA tanks are.....open top I think for this reason, as are my own tanks, but I do this more for ease of horticulture and working on the tanks, and the aesthetic.

25-30 is a bit on the lower end......microswords are fine...but most want a bit more for those 2 stem species to garden them well.


----------



## Yiannis

How do I tell the difference between a T5NO and T5HO?


----------



## robbowal

Yiannis said:


> How do I tell the difference between a T5NO and T5HO?


With all the hagen Glo bulbs it is marked on the packaging and printed on the bulb. i believe it is marked on the other brands as well.


----------



## Yiannis

Lets say that I have 2 x 36W T5NO (since its not T5HO I guess) over a 58cm tall tank and that the lights are 5cm above the tank. Is it low medium or high? I really dont get this sorry...


----------



## robbowal

to quote from JasonG75 post 
"*2 T5No on top of the tank will give you Med lighting*.
1 T5Ho on top of the tank will give you Med lighting.

2 T5No 4" above the tank will give you Med lighting.
1 T5Ho 4" above the tank will give you Med lighting.
2 T5Ho 4" above the tank will give you High Ligh.

1 T5Ho 12" above the tank will give you Low lighting.
2 T5Ho 12" above the tank will give you Low lighting.
3 T5Ho 12" above the tank will give you Med Light."

hope that helps


----------



## 2in10

Yiannis said:


> Lets say that I have 2 x 36W T5NO (since its not T5HO I guess) over a 58cm tall tank and that the lights are 5cm above the tank. Is it low medium or high? I really dont get this sorry...


On T5HO bulbs 24" bulbs are 24 watts, 36" bulbs 39W, 48" bulbs 54W, 60" bulbs are 80W.


----------



## Hoppy

A T5NO light made with very good reflectors is a rarity, if it even exists. Most T5NO lights have poor reflectors. That makes it difficult to guess how much PAR you get from one. Enough people have measured the PAR from Coralife T5NO lights to make it reasonably easy to guess how much PAR those give you, but I'm not sure all Coralife T5NO lights have always had the same bad reflector. Based on the PAR readings I have seen, I believe a Coralife T5NO gives about the same PAR per bulb as a typical T8 bulb. A 2 bulb light should give you twice the PAR of a one bulb light.


----------



## Yiannis

So I found out that I have two 4 Pin PLL 36W lights with reflectors just like this one http://www.lightbulbs-direct.com/product/2212/pll-compact-36w-865-daylight-2g11-4-pin/ over a 90L tank 58 cm in height. How does that sound?


----------



## Hoppy

Yiannis said:


> So I found out that I have two 4 Pin PLL 36W lights with reflectors just like this one http://www.lightbulbs-direct.com/product/2212/pll-compact-36w-865-daylight-2g11-4-pin/ over a 90L tank 58 cm in height. How does that sound?


It is probably low light. If the reflectors are about twice the width of the bulbs, and shaped so you can see a reflection of each bulb on each side of the bulbs, and some reflection of the back of the bulb in those two reflections, you could have low medium light.


----------



## chrisinmontreal

Thanks for some great info. Complete newbie to planted tanks here. What I thought was a low light setup based on Watts/gallon looks by your table to actually be too high light!!

I have a 24" T5HO Hagen Glo double bulb fixture above a 30" wide by 16" deep tank. I now mounted the lights suspended from the ceiling at a 10" height above the tank for a medium light setup. Sound about right to you?


----------



## Hoppy

I don't recall ever seeing any PAR measurements for Hagen Glo lights, but their reflectors are not as good as the best ones for T5HO lights. As a guess you could use the line on the chart for AH Supply lights for what the Hagen Glo lights give you. Based on that, a two bulb Hagen Glo at 24 inches from the substrate would give you about 60 micromols of PAR, which is medium light.


----------



## woolf7117

I am going to set up an 11 gallon with a tank height of 12". I'll be using CO2, as well. Could I get confirmation of what I think I've learned from my reading of this thread?

- I don't need a T5HO;
- A power compact setup would be an efficient alternative to the T5HO;
- AH Supply offers good quality merchandise, including a good reflector; and
- The 2 x 36 watt Bright Kit should meet my needs.

Appreciate any feedback and/or correction.


----------



## singtoh

Hello Hoppy,

Thanks for all of your testing and work on the lighting. I am a bit confused though. I have 2 T5NO lights each with it's own DIY reflectors. They are mounted in a custom hood and from the bottom of the bulbs to the substrate is close enough to 16 inches. The tubes are about 3 inches from the waters surface and can't be raised any further. Going by the light intensity chart it says that I am at low light. But looking at the Par vs. Dist graph if I am reading it correctly I think it says that I am nearly high light. Call me daft, no problem I just wanted to be sure. Also, my DIY reflectors are parabolic with 3 facets either side of the tube, lined with aluminium tape, it could be mylar, I am not sure but its not very shiny. I was wondering if it would help to polish to make it specular or would that defeat me seeing how the angles aren't perfect, light restrike and all the rest or would difused reflection be better in my case??. I polished a bit of the tape to a mirror finish in a couple of minutes with some Braso polish, so it's pretty easy to do. I can get IceCap reflectors here at about $25 dollars apiece, but if my lighting is edging to the high side?? maybe I should just stick with the reflectors I have?? Sorry if I am a daft twit and not seeing something correctly on the chart/graph, it seems you are very busy on here.

Cheers,

Singtoh


----------



## Hoppy

woolf7117 said:


> I am going to set up an 11 gallon with a tank height of 12". I'll be using CO2, as well. Could I get confirmation of what I think I've learned from my reading of this thread?
> 
> - I don't need a T5HO;
> - A power compact setup would be an efficient alternative to the T5HO;
> - AH Supply offers good quality merchandise, including a good reflector; and
> - The 2 x 36 watt Bright Kit should meet my needs.
> 
> Appreciate any feedback and/or correction.


The most favorable light intensity, in that it reduces algae problems, slows the plant growth, and allows you to grow any plants you want, is 40-50 micromols of PAR. More than that just adds to the maintenance required, and makes you become an algae fighter instead of a plant grower. A 12 inch high tank can get that light level without raising the light well above the top of the tank with T8 lights only. An AH Supply light will give you way too much light.

An alternative to T8 lights is screw-in power saver CFL lights, where you can select a wattage that gives you the PAR you need. See the other sticky for more information on those lights.


----------



## Hoppy

singtoh said:


> Hello Hoppy,
> 
> Thanks for all of your testing and work on the lighting. I am a bit confused though. I have 2 T5NO lights each with it's own DIY reflectors. They are mounted in a custom hood and from the bottom of the bulbs to the substrate is close enough to 16 inches. The tubes are about 3 inches from the waters surface and can't be raised any further. Going by the light intensity chart it says that I am at low light. But looking at the Par vs. Dist graph if I am reading it correctly I think it says that I am nearly high light. Call me daft, no problem I just wanted to be sure. Also, my DIY reflectors are parabolic with 3 facets either side of the tube, lined with aluminium tape, it could be mylar, I am not sure but its not very shiny. I was wondering if it would help to polish to make it specular or would that defeat me seeing how the angles aren't perfect, light restrike and all the rest or would difused reflection be better in my case??. I polished a bit of the tape to a mirror finish in a couple of minutes with some Braso polish, so it's pretty easy to do. I can get IceCap reflectors here at about $25 dollars apiece, but if my lighting is edging to the high side?? maybe I should just stick with the reflectors I have?? Sorry if I am a daft twit and not seeing something correctly on the chart/graph, it seems you are very busy on here.
> 
> Cheers,
> 
> Singtoh


T5NO lights have usually been the Coralife brand, and those have very poor reflectors. They give about the same amount of light per bulb as T8 lights. When you improve the reflectors you get more light, but I don't know any good way to guess how much more light. You really need to use a PAR meter to find out how much light your particular T5NO setup is giving you. One thing I have learned is that a simple \_/ shaped reflector made of aluminum, with the bends made so you can see an image of the bulb on each side of it, will double the PAR from fluorescent bulbs. You can use that to arrive at a guess about how much light you are getting.


----------



## singtoh

Hoppy said:


> T5NO lights have usually been the Coralife brand, and those have very poor reflectors. They give about the same amount of light per bulb as T8 lights. When you improve the reflectors you get more light, but I don't know any good way to guess how much more light. You really need to use a PAR meter to find out how much light your particular T5NO setup is giving you. One thing I have learned is that a simple \_/ shaped reflector made of aluminum, with the bends made so you can see an image of the bulb on each side of it, will double the PAR from fluorescent bulbs. You can use that to arrive at a guess about how much light you are getting.



Ok, thanks Hoppy. The shape of the reflector is similiar to the above. I can see the image of the bulbs on either side of the reflector, not clearly but they are there. I am itching to get some shiny new Icecap reflectors :icon_smil, but I was afraid that it might push my light too high. But as I said, I am a bit confused with the chart and graph. The graph starts out at 5 inches from the water, and my tank its 3inches from the water, so if I am reading the graph correctly I am already in the high light range and getting better reflectors would just make problems for me??? Thanks again for the reply Hoppy, I appreciate it. :icon_smil.

Cheers,

Singtoh


----------



## Yiannis

Would this lighting fixture be adequate for a 90L aquarium 60cm height? To grow DHG with co2.

Ebay number: 260833089112 
NEW 48w 24" aquarium light 2 feet fixture T5 HO lamp


----------



## Hoppy

singtoh said:


> The graph starts out at 5 inches from the water, and my tank its 3inches from the water, so if I am reading the graph correctly I am already in the high light range and getting better reflectors would just make problems for me??? Thanks again for the reply Hoppy, I appreciate it. :icon_smil.
> 
> Cheers,
> 
> Singtoh


The distances shown on the graph are distances from the substrate, or distances from the light to where the PAR is measured. So, the 5 inches means a tank 5 inches high, or the PAR measured 5 inches from the bulb.


----------



## Hoppy

Yiannis said:


> Would this lighting fixture be adequate for a 90L aquarium 60cm height? To grow DHG with co2.
> 
> Ebay number: 260833089112
> NEW 48w 24" aquarium light 2 feet fixture T5 HO lamp


That light looks a lot like an Odyssea light, which has been reviewed and its light output measured with a PAR meter, on another website. If it is one of those, and the ballast sure looks like it is, it will be a little more effective than a typical T5NO light, but not nearly as good as a typical T5HO light. It would then give you only about 30-40 micromols of PAR, which would be marginal for growing DHG.


----------



## Gafi

just a quick question...if plants are in the middle of the aquarium...say 8-10 inches from the light source (using T8 bulb) does that mean those plants are considered to be in the medium light range....and the plants that would be right at the substrate (1-2 inches above sub and 10-12inch below light) in the low light category?


----------



## Yiannis

Hoppy said:


> That light looks a lot like an Odyssea light, which has been reviewed and its light output measured with a PAR meter, on another website. If it is one of those, and the ballast sure looks like it is, it will be a little more effective than a typical T5NO light, but not nearly as good as a typical T5HO light. It would then give you only about 30-40 micromols of PAR, which would be marginal for growing DHG.


Please explain what you just said  I mean if it is T5HO why would it be less effective than other T5HOs?


----------



## singtoh

Hoppy said:


> The distances shown on the graph are distances from the substrate, or distances from the light to where the PAR is measured. So, the 5 inches means a tank 5 inches high, or the PAR measured 5 inches from the bulb.


Ok Hoppy, thanks for the clarification on that. I was reading it wrong as usual, and feel a bit better knowing that I am safely in the low light range. I'll stick with what I have for awhile and see how it goes before throwing any money at IceCap reflectors. Thanks again Hoppy, good stuff :icon_smil.

Cheers,

Singtoh


----------



## Hoppy

Gafi said:


> just a quick question...if plants are in the middle of the aquarium...say 8-10 inches from the light source (using T8 bulb) does that mean those plants are considered to be in the medium light range....and the plants that would be right at the substrate (1-2 inches above sub and 10-12inch below light) in the low light category?


Light intensity drops off proportional to the square of the distance from the source, roughly. So, any aquarium not lit by the sun will have a higher PAR near the water surface than at the substrate. If the light sits right on top of the tank, the difference in intensity can be pretty big, while having the light a couple of feet above the tank greatly reduces that difference.



Yiannis said:


> Please explain what you just said  I mean if it is T5HO why would it be less effective than other T5HOs?


With fluorescent bulbs the intensity of the light depends on how much current flows through the bulb and the technology involved in the bulb - T5HO bulbs are inherently brighter, especially when driven at the higher current that T5HO bulbs are designed for. The Odyssea light that was examined and had its PAR measured was found to use magnetic ballasts, that did not force the bulbs to operate at that high current. And, it had relatively poor reflectors. Those two things make it be less effective than T5HO lights using modern electronic ballasts that drive the bulb at the design current, and which have very good reflectors. This may not be true of all of the Odyssea lights, but I wouldn't want to assume it isn't. Those lights should be fine where you don't want the full brightness of typical T5HO lights, which would be for most tanks with the light less than about 30 inches from the substrate, or where you actually want to use high light.


----------



## Yiannis

Hoppy said:


> Light intensity drops off proportional to the square of the distance from the source, roughly. So, any aquarium not lit by the sun will have a higher PAR near the water surface than at the substrate. If the light sits right on top of the tank, the difference in intensity can be pretty big, while having the light a couple of feet above the tank greatly reduces that difference.
> 
> 
> With fluorescent bulbs the intensity of the light depends on how much current flows through the bulb and the technology involved in the bulb - T5HO bulbs are inherently brighter, especially when driven at the higher current that T5HO bulbs are designed for. The Odyssea light that was examined and had its PAR measured was found to use magnetic ballasts, that did not force the bulbs to operate at that high current. And, it had relatively poor reflectors. Those two things make it be less effective than T5HO lights using modern electronic ballasts that drive the bulb at the design current, and which have very good reflectors. This may not be true of all of the Odyssea lights, but I wouldn't want to assume it isn't. Those lights should be fine where you don't want the full brightness of typical T5HO lights, which would be for most tanks with the light less than about 30 inches from the substrate, or where you actually want to use high light.


Ok now I understand. Thanks. Could you please explain how one can choose to get a T5HO system? What should I look for in order to understand if it is strong enough?

Also could you please recommend a light fixtrue, a known product, for a 60 cm (24inches) tall tank? The tank is 90L in volume


----------



## woolf7117

Hoppy said:


> The most favorable light intensity, in that it reduces algae problems, slows the plant growth, and allows you to grow any plants you want, is 40-50 micromols of PAR. More than that just adds to the maintenance required, and makes you become an algae fighter instead of a plant grower. A 12 inch high tank can get that light level without raising the light well above the top of the tank with T8 lights only. An AH Supply light will give you way too much light.
> 
> An alternative to T8 lights is screw-in power saver CFL lights, where you can select a wattage that gives you the PAR you need. See the other sticky for more information on those lights.


As you suggested, I checked the other sticky. It made me feel better about going with the spiral CFL. I've got a 28W GE 6500K in an IKEA desk lamp, trying to grow glosso with pressurized CO2.

Thank you for your feedback!


----------



## plamski

*Catalina 4x54W and 72gal Bowfront*

Hey,Hoppy. Thanks for the great thread.
I just bought 72gal Bowfront tank 22” high .I’ll add 3-3.5” substrate to it. I’ll have pressured CO2 , very light ferts schedule and 30% water changes every 2 months. Plants-java fern, moss, crypts,marsela minuta, anubias, tropica 49 etc.
Light is Catalina Black Solar 48” 4x54W.Bulbs 6500K, Plant Grow. I’ll use 2 bulbs only. Light will be tilted little bit to the back because it’s too bright for our eyes. I have 2 questions.
Which bulbs to use -1 and 3 or 1 and 4 fixture is 8” wide?
How far from substrate it should be lifted?


----------



## Yiannis

Could someone post links of good lighting fixtures that sit right on top of the tank so as to see if I can get them here in cyprus? e.g is this any good for a 60cm tall and 60cm long tank?

http://www.aquaessentials.co.uk/arcadia-freshwater-ot5-luminaire-2-x-24w-26-p-2240.html


----------



## Hoppy

plamski said:


> Hey,Hoppy. Thanks for the great thread.
> I just bought 72gal Bowfront tank 22” high .I’ll add 3-3.5” substrate to it. I’ll have pressured CO2 , very light ferts schedule and 30% water changes every 2 months. Plants-java fern, moss, crypts,marsela minuta, anubias, tropica 49 etc.
> Light is Catalina Black Solar 48” 4x54W.Bulbs 6500K, Plant Grow. I’ll use 2 bulbs only. Light will be tilted little bit to the back because it’s too bright for our eyes. I have 2 questions.
> Which bulbs to use -1 and 3 or 1 and 4 fixture is 8” wide?
> How far from substrate it should be lifted?


I would raise it about 6 inches above the top of the tank and use any two of the bulbs. You could use one pair of bulbs for 4 hours, and the other pair for the next 4 hours. Or you could have all 4 bulbs on for an hour in the middle. 

Don't under fertilize. That would slow the plants growth rate which helps algae get a good start. And, use enough CO2 so the plants pearl for most of the day.


----------



## plamski

"Don't under fertilize. That would slow the plants growth rate which helps algae get a good start. And, use enough CO2 so the plants pearl for most of the day." 

OK but how to fertilize and to do water changes ones per 2-3 months?


----------



## forddna

I may have missed it, but how far apart to two T5HO bulbs need to be to not double PAR? (to be considered single bulb fixtures, IOW)


----------



## Hoppy

forddna said:


> I may have missed it, but how far apart to two T5HO bulbs need to be to not double PAR? (to be considered single bulb fixtures, IOW)


I don't know, but I do know that about 8 inches greatly reduces how the two PARs add up. And, that is for a light about 2 feet from the substrate. I suspect that the farther from the light the more the two lights add their PARs.


----------



## forddna

Gotcha. I'm trying to find the most economical way for me to reduce my light intensity/PAR. My tank is 22" tall, substrate is about 2.5" and lights are 8" above water, IIRC. I'm thinking of just running two 24w T5HOs spread apart. I currently have them close together with another 70w HQI filling in the back corner.

My goal is to not need CO2 and to be able to slack off on ferts. I mostly want a tank I can leave alone. (short on spare time and ambition)


----------



## forddna

Measured everything. My water is 19" deep, and my lights are 27" from the substrate. I think I can easily get the two strips 6" apart. Is that enough distance between them (see above post)??

Your graph puts that into the Medium range (as single bulb fixture) but your chart says Low. What are your thoughts on this, Hoppy? Thank you for your help.


----------



## Hoppy

forddna said:


> Measured everything. My water is 19" deep, and my lights are 27" from the substrate. I think I can easily get the two strips 6" apart. Is that enough distance between them (see above post)??
> 
> Your graph puts that into the Medium range (as single bulb fixture) but your chart says Low. What are your thoughts on this, Hoppy? Thank you for your help.


It could be either low or medium, depending on how good the reflectors are, and if the ballast is driving the bulbs at the full wattage. I don't know if 6 inches is enough or not, but it should be a lot less light than with the bulbs side by side. Again, it also depends on the reflectors, too.


----------



## MsNemoShrimp

Unfortunately the charts on here doesn't help me find out what type of lighting my setup would fall under. There is the thread with more details:

http://www.plantedtank.net/forums/lighting/149107-12g-long-mr-aqua-w-26w.html


----------



## forddna

Hoppy said:


> It could be either low or medium, depending on how good the reflectors are, and if the ballast is driving the bulbs at the full wattage. I don't know if 6 inches is enough or not, but it should be a lot less light than with the bulbs side by side. Again, it also depends on the reflectors, too.



They are good reflectors, but I do not recall which brand. The ballast is Accustart.


----------



## Ziggy

I'm planning my next (low tech) setup around either a 15G or 20G "long", either of which would be 12" high. I had assumed I'd use a single T5HO directly on top but after stumbling on this thread and seeing the chart at the beginning it seems that would be too much even for high tech! Do I read that right? Would a single T8 be a better idea?


----------



## plamski

Ziggy said:


> I'm planning my next (low tech) setup around either a 15G or 20G "long", either of which would be 12" high. I had assumed I'd use a single T5HO directly on top but after stumbling on this thread and seeing the chart at the beginning it seems that would be too much even for high tech! Do I read that right? Would a single T8 be a better idea?


I have some 20gal long shrimp tanks. Substrate Aquasoil I, no FERTS or CO2 .PH 6.2-6,5
Light is single 18W-if I’m not mistaken -6700 T5NO lifted 4”-5” over the tank. Plants are growing slow but nice 100% algae free. I have there: Blyxa Japonica,Cabomba,Hydrocotyle Leucocephala,Hygrophila difformis, Hygrophila “Sunset”,Ludwigia ovalis,Micranthemum umbrosium,Myriophyllum mattogrossensegreen,Staurogyne sp “porto velho”.
I have one 20gal long PH-8.0 with regular substrate. There are 2xT8 24” bulbs lifted 7”-9” over the tank and it is growing Algae like crazy.
My photo period is 12h on all tanks.
I have better results when light are at least 4” over the tanks.


----------



## BonesCJ

Question, In the charts the T8's only go up to 3 bulbs. I have a 210 (24 inches tall) that I setup with 4 36inch fixtures each mouting 2 bulbs. The lights are about a foot off the surface, I was shooting for a low light tank, does this qualify? The entire canopy is painted white.

so the layout is four rows of bulbs from front to back and 2 bulbs per row lengthwise. The tank is 7 feet long. So 8 bulbs total.


----------



## BonesCJ

Oh and the bulbs are 25 watts each, so 200 watts of light, mix of 6500k ultra sun and florasun plant bulbs


----------



## dundee

BonesCJ said:


> Question, In the charts the T8's only go up to 3 bulbs. I have a 210 (24 inches tall) that I setup with 4 36inch fixtures each mouting 2 bulbs. The lights are about a foot off the surface, I was shooting for a low light tank, does this qualify? The entire canopy is painted white.
> 
> so the layout is four rows of bulbs from front to back and 2 bulbs per row lengthwise. The tank is 7 feet long. So 8 bulbs total.


With that layout you effectively have 4 bulbs running almost the length of the tank.

You need to measure from the light to the substrate. But with the data you gave 24" tall tank plus 12" from the surface is 36" total. Hoppy's chart doesn't include enough data for your setup.

However in my *opinion*, based on the his chart and my experience & research you should be low light and can grow low light plants.

I recommend starting with what you have then if you want more light you can either lower the fixture or overdrive those T8s :icon_twis


----------



## Rainer

I'm running a 24w LED bar over a 10g halfmoon tank but I'm no longer satisfied with the results. The tank rim is 15" above the substrate with the lights 1.25" above that. The two alternatives I'm considering are 25w-26w CF bulbs (not spiral). Going strictly by wattage, all three lights are roughly identical. 

1. Is there a significant PAR difference between the CFs and the LEDs?

2. If not, would doubling up the CF fixtures be my best bet? I'm dosing Excel and don't want to get into DIY CO2 territory.

3. Is there any reason to prefer one CF over the other?


Current LED:











CF Option 1









CF Option 2:


----------



## Surgeon

Well Im setting up a 6ft long, 2ft wide 16 inch high tank and from hoppys chart im on the high end of high! 1 2ft x 2bulb T5HO hagen GLO + 1 4ft 2bulb T5HO hagen GLO.

Probably more complicated than that though as the 2 bulb solutions have a much wider beam by the time they hit the substrate (I was lucky enough to have 2x3ft single t5HO's to test with). The Single bulb reflectors covered maybe 3/4 of the bottom of the tank leaving part in darkness. The 2 bulb prettymuch covers the full 2ft.

Oh well I'll figure out ways to reduce the PAR if it becomes a problem. I have a couple of floating plants on order


----------



## forddna

Try without a reflector?


----------



## Surgeon

forddna said:


> Try without a reflector?


First thing I'll try is some small mirrors to bounce light around more (2ft is rather wide). The reflectors are part of the unit but I can cover them if its needed.


----------



## Mannie Bothans

WOW. This is FANTASTIC. Thank you so much!! I have never had an aquarium before and this is very helpful.

I am totally new to all of this, and I want to try to increase my chances of hitting the sweetspot to not need extra CO2 and not just feed the algae.

It appears as though there is a great disparity between different brands of products. If my budget wasn't so "low-tech" it would be amazing to invest in a PAR meter.

My new tank came with a T8 24inch single 20w white-"reflector" Perfecto strip. Today, before reading this thread, I just went out and bought the best I could find locally: an Aqueon brand dual-lamp, 30inch long set with a very square mirror reflector and 2 included 18W(each) T5-sized bulbs.

My tank is probably going to be difficult to light properly. It is a 56Gallon tank that is 30inches wide, 18inches from front-to-back, and 24inches tall.

This is a picture of what I now have:
http://dl.dropbox.com/u/12554833/lights.jpg

I have absolutely no idea how bad (or good) these ballasts are, but it seems pretty obvious what these reflectors are like.

I am trying to wrap my brain around exactly what the micromols might be at the very bottom, middle, and top of my tank if I used exactly what I have now.

I'm guessing maybe it would yield low light at the very bottom and mid-to-high at the very top if I used all three bulbs? I have a big hunk of driftwood that I could use as an elevated planter to get the plants closer to the top, if I absolutely had to.

I don't want the plants to grow incredibly quickly. Low-tech and low-maintenance is quite preferable-- but my main concern is not creating the perfect recipe for algae. 

My water will be maintained between 65° and 68° if that matters (regarding the algae issue).

Do I need both of the sets that I have now or does putting them both together do absolutely nothing toward getting more light into the recesses of the bottom of the tank?

If this setup is particularly bad, can these ballasts safely accomodate higher wattage bulbs? The T8 is rated 60 Hz (if that means anything) and I don't know about the dual T5.


----------



## Storm

Hoppy said:


> The T5HO line on the first chart has been difficult to apply, because so many cheap T5HO lights with less than good reflectors are now available. To make it easier to estimate how much light you can get from different quality T5HO lights, try this chart:
> 
> 
> 
> 
> 
> 
> 
> 
> And, to judge the quality of the reflectors:


Wow, this is totally awesome with this new chart, and answers many of my questions regarding low cost T5HO fixtures. Based on your new chart, would you consider the Fishneedit fixture to have "fair" reflectors? They're not exactly separate, but there is an angled piece of metal between the two bulbs.


----------



## Mannie Bothans

Thank you so much. I have two bulbs (so data x2) and very poor bulb configuration (so data /2 ). This means without my extra t8, I should have the bottom end of the low light zone at the bottom of the tank and the high end of the high light zone at the top of my tank.


----------



## Hoppy

Storm said:


> Wow, this is totally awesome with this new chart, and answers many of my questions regarding low cost T5HO fixtures. Based on your new chart, would you consider the Fishneedit fixture to have "fair" reflectors? They're not exactly separate, but there is an angled piece of metal between the two bulbs.


That looks like a "fair" reflector to me. 

I think the typical Catalina Aquarium reflector is likely somewhere between fair and very good. I know the one I tested wasn't as good as the very good ones, but it was an old fixture too.


----------



## DaTrueDave

Seattle_Aquarist said:


> Hi All,
> 
> A new player in town; AH Supply T5HO linear! I hope to see them in operation at Erik Olson's in the near future! Prices seem competitive.


First post here. This thread caught my eye, as I'm setting up a tank after a decade away from the hobby.

I've realized that four 40W T12 lights is no longer considered ideal for a standard 55gal planted tank (lamps about 20" above substrate). Wouldn't one of these 2x54watt T5HO kits be ideal? Or, even better, two separate 1x54watt kits, which would allow me to turn on only one lamp until I get my CO2 rig set up and I turn on the second lamp.

Am I right in thinking that these T5HO linear kits are a superior choice to the 2x55watt Bright Kits?

I've already got a decent canopy in which to mount this type of kit. With that in mind, does anyone have any other suggestions for a 55gal?


----------



## dmastin

wowwee
I'm getting back into the hobby with my 50 gallons (36 L x 18W x 19H inches) aquarium and I'd pretty much never thought more than watts per gallon and duration. 
I have a Catalina Aquarium light fixture with 4 t5HO bulbs 4 inches above the water line with I'm assuming reflectors fair to good. I even purchased a Coralife two bulb T5 fixture that sits almost on the water as a supplement. I was shooting for 39w x 1-6 depending on how many are turned on, but I am to understand current thinking is anything over two of these bulbs might be too much light? thanks for your work and any advice -David


----------



## Craigthor

Hoppy any idea how MH fits in this graph? I've 3- 150 watt MH over my 6' 150g tank lights are about 36" from teh substrate.

Craig


----------



## DKRST

What is the PAR "range" for low light, and medium light? The graph is clear to me, but I'm getting differing numbers from other thread's on this forum.
Should I measure my tank PAR at the substrate or at, mid-level? Interestingly, my PAR values don't shift much between my mid-tank and substrate level (35-32 micromoles). This tank is only 14" deep, with a 2" sand substrate.
I have a PAR meter, fortunately!
I've read the entire thread, it's getting long, but it has been really helpful.


----------



## Hoppy

DaTrueDave said:


> First post here. This thread caught my eye, as I'm setting up a tank after a decade away from the hobby.
> 
> I've realized that four 40W T12 lights is no longer considered ideal for a standard 55gal planted tank (lamps about 20" above substrate). Wouldn't one of these 2x54watt T5HO kits be ideal? Or, even better, two separate 1x54watt kits, which would allow me to turn on only one lamp until I get my CO2 rig set up and I turn on the second lamp.
> 
> Am I right in thinking that these T5HO linear kits are a superior choice to the 2x55watt Bright Kits?
> 
> I've already got a decent canopy in which to mount this type of kit. With that in mind, does anyone have any other suggestions for a 55gal?


The best light level, and it is all the light you need, is around 40-50 micromols of PAR. A good T5HO light, with one bulb, gives you more than that on a typical 55 gallon tank. A two bulb light has to hang at least 8-10 inches above the tank or you have too much light for comfort.

A T5HO light is only superior to an AH Supply light if you need more light, and because it uses less electricity.



dmastin said:


> wowwee
> I'm getting back into the hobby with my 50 gallons (36 L x 18W x 19H inches) aquarium and I'd pretty much never thought more than watts per gallon and duration.
> I have a Catalina Aquarium light fixture with 4 t5HO bulbs 4 inches above the water line with I'm assuming reflectors fair to good. I even purchased a Coralife two bulb T5 fixture that sits almost on the water as a supplement. I was shooting for 39w x 1-6 depending on how many are turned on, but I am to understand current thinking is anything over two of these bulbs might be too much light? thanks for your work and any advice -David


The light will be around 20 inches from the substrate, and Catalina light reflectors are somewhere between very good and fair, so a single bulb should give you about 50-60 micromols of PAR. Even 2 bulbs is overkill.



Craigthor said:


> Hoppy any idea how MH fits in this graph? I've 3- 150 watt MH over my 6' 150g tank lights are about 36" from teh substrate.
> 
> Craig


I have done nothing with MH lights, but I know they can be much brighter than T5HO. There are several varieties of MH lights, too, which would mean one would need a lot of data to really understand how much PAR they produce.



DKRST said:


> What is the PAR "range" for low light, and medium light? The graph is clear to me, but I'm getting differing numbers from other thread's on this forum.
> Should I measure my tank PAR at the substrate or at, mid-level? Interestingly, my PAR values don't shift much between my mid-tank and substrate level (35-32 micromoles). This tank is only 14" deep, with a 2" sand substrate.
> I have a PAR meter, fortunately!
> I've read the entire thread, it's getting long, but it has been really helpful.


The PAR from a T5HO or T8 or PC light decreases proportional to the square of the distance from the light - at twice the distance the PAR is 1/4 as much. So, you kind of have to pick one depth of the tank to measure the PAR if you want to characterize different lights. I chose the substrate level because virtually all plants start growing there first, and carpet plants stay there. This type of analysis is only an estimate of the amount of PAR you get, and it lumps all lengths of bulbs together, which is a good rough estimate, but not a perfect one by any means. Also, as you get closer to a long fluorescent tube only the light from a short length of the tube reaches the sensor, so the PAR no longer follows the "inverse square" rule at all closely, becoming more like a direct relationship between PAR and distance. Still, the PAR near the water surface will always be much higher than at the substrate level. If the light is hanging as far above the tank as the tanks height, the inverse square relationship should be very nearly perfect for the whole tank.

The PAR ranges for low light, medium light, and high light are a little bit arbitrary. With even 20 micromols of PAR some plants will grow slowly, and with CO2 more will do so and faster. With 50-60 micromols of PAR CO2 is almost necessary to keep from constant battles with BBA, but Excel might be adequate. Much above 60 micromols of PAR and CO2 is essential. Eventually the concentration of CO2 needed to keep the plants in healthy growth, which is what discourages algae, becomes higher than the fish can live with. That is likely to be somewhere around 90+ micromols. And, at 40-50 micromols, if you also use good CO2 concentration and non-limiting fertilizing, you should be able to grow any plants you want to. So, why not just use 40-50 micromols if you have CO2, and 30 or so micromols if you don't?


----------



## fullmonti

Great thread

I have a couple question about lighting. I'm changing a 180 reef to a planted tank. I already have two 48" 2bulb T5 fixture & metal halide as well. I like the shimmer effect of the MH fixture. One question is, as long as I get the PAR level right is there any problem using MH mixed with T5s in a planted tank? If not do you know if any brand of MH bulb is better for plants?

Jim


----------



## fishyjoe24

hobby where would the zoo-med fixtures fit in to play.. they are t5 h.o. with a single reflector that is box shaped, or what about the current nova's with t5 h.o. 4 bulbs with a single reflector that is "c" shaped with it being flat on the top... I want to grow glosso in a 29g, along with rotella wallichi and rotella incida. i want to keep the the incida pinkish with it's green and the wallichi red. will the zoomed 2 bulb t5 h.o. 2 inch above the tank with c02 work, or would i need the 4 bulb t5 h.o. i'm trying to save some money. the 4 bulb is 24 inches, and i already have it. the zoomed comes in a 30 inch and uses 24 inch bulbs.


----------



## fishyjoe24

fullmonti said:


> Great thread
> 
> I have a couple question about lighting. I'm changing a 180 reef to a planted tank. I already have two 48" 2bulb T5 fixture & metal halide as well. I like the shimmer effect of the MH fixture. One question is, as long as I get the PAR level right is there any problem using MH mixed with T5s in a planted tank? If not do you know if any brand of MH bulb is better for plants?
> 
> Jim


MH work for planted tanks. i'd stay in the 5,000 to 10,000k I've seen 8,000k on a planted tank and it looks wonderful it's a 210 and it has 2 if i remember 250w bulbs or 150w bulbs x 3.


----------



## Robert H

> A T5HO light is only superior to an AH Supply light if you need more light, and because it uses less electricity.


This confuses me. Kim at AH supply insists that power compacts are T5HOs, just U shaped instead of linear and they give off the same amount of light. Because it is U shaped, it takes up the same amount of space as a linear, but if straightened out would be twice as long. This is why a PC is higher wattage, and it should be twice as bright as a linear T5HO... shouldn't it?


----------



## audioaficionado

There is more restrike on the inner folded back area on a PC, while a straight T5HO doesn't have that problem.


----------



## ghotifish

*Fantastic info*

This post really needs to be added tor the FAQ section!!!


----------



## Robert H

If you are interested, Hoppy has written a new article with updated charts:

How to gauge aquarium lighting for the planted aquarium


----------



## barbarossa4122

Robert H said:


> If you are interested, Hoppy has written a new article with updated charts:
> 
> How to gauge aquarium lighting for the planted aquarium


Thanks for the link and many thanks to Hoppy.


----------



## Hoppy

Robert H said:


> This confuses me. Kim at AH supply insists that power compacts are T5HOs, just U shaped instead of linear and they give off the same amount of light. Because it is U shaped, it takes up the same amount of space as a linear, but if straightened out would be twice as long. This is why a PC is higher wattage, and it should be twice as bright as a linear T5HO... shouldn't it?


AH Supply lights are T5, as far as the diameter of the tubes is concerned, and they are driven at T5HO power levels, but they can't equal T5HO's because you can't get a reflector around each half of the tube, only halfway around. That limits the gain you get from the reflector. Still, they do come close to good T5HO lights as far as the amount of PAR you can get is concerned.

Because they are half the length of a T5HO of roughly the same power, they can only light half as much of the tank as a T5HO - it takes two 55 watt AHS lights to replace one 54 watt T5HO light on a 4 foot long tank. And you get a bit less light with the AHS lights, but use twice the power.


----------



## dafil

Hoppy,what watage bulbs did you use when you made this chart?
I think that there will be a diference if you use 54w bulb at 20 inches/for instance/ and 24w bulb at same distance.Assuming that the par meter is in the midle of the bulb lenght.


----------



## beastoise

nvm. taken care of.


----------



## Aquaticz

Ahhhh My head is spinning.....I am looking for opinions - yours  

I replaced an odd sized tank yesterday 36 X 10 X 17 that I would like to run as a low light tank without CO2. In reading many pages I learned that the best plant growth occurs when the lighting is 12 inches about the top of the tank. Herein lies my query.....
At 12 " above the top of the tank am I best off with a T-5? I ask because with the light being above the tank I am concerned about how that is on the eyes.. as the tank will be be in a room with my other six tanks & all have fixtures on top of the tank. Maybe I am better off in my situation to put the fixture on top so that the new tank does not "stick out" unfavorably. 

In the past I made my own DIY fixtures with parts from A& H Supply. 4 X 55 watt
One of the reason for a low light tank (less trimming) 

So ...what do you think- which way should I go for a low maintenance tank 
1. 12 " above with ______________ type of lighting at ____watts 
or
2. right on top with the substrate being about 15" from the top with ____________type of lighting at _________watts.

less power is always better -my bill is right about 400.00 a Month!


----------



## Hoppy

I think a non-CO2 tank should get between about 20 and 30 micromols of PAR at the substrate. And, to avoid the plants bolting to the surface once they grow a few inches tall, I think it is best to have the light high above the top of the tank. This also reduces algae problems in the upper parts of the tank. So, your tank is 17 inches high, with 2 inches of substrate, and it is 36 inches long. Since it is 10 inches front to back depth, you can easily light the whole tank with a single strip light.

A Coralife (Aqueon) 2 bulb 36 inch T5NO light sitting on top of the tank will work well.
A custom made Catalina 1 bulb 24 inch T5HO light, 12 inches above the top of the tank will work well. The ends of the tank will be a bit lower in light than the middle. A 36 inch long light will avoid that, but give more spillover light at the ends.
The same Catalina 1 bulb light will work well at 15 inches above the top of the tank.


----------



## Aquaticz

You are awesome Hoppy thanks for your knowledge & willingness to assist "-)

also GREAT Timing
I am off to SCAPE's Grand raffle meeting today in Carson .... So I'll probably get the fixture while I am there plus a bucket or two of plants and goodies 

How about wattage......... 39w ????



Currently all my higher light tanks are on CF by A&H 55 w


----------



## Hoppy

39 watt T5HO means 36 inches long. If you decide to go with that length, then 39 watts is the right number. But, if you decide to use a 24 inch long light, 24 watts is the right number. Watts aren't a measure of light, just of the electric power consumed by the light.

Don't assume that all T5HO lights are equal. They aren't. Some have very poor reflectors, underpowered ballasts, and give far less light than you expect. That's why I recommended the Catalina Aquarium light, which I have data from. A FishNeedIt light would give far less light.


----------



## Aquaticz

Hoppy said:


> 39 watt T5HO means 36 inches long. If you decide to go with that length, then 39 watts is the right number. But, if you decide to use a 24 inch long light, 24 watts is the right number. Watts aren't a measure of light, just of the electric power consumed by the light.
> 
> Don't assume that all T5HO lights are equal. They aren't. Some have very poor reflectors, underpowered ballasts, and give far less light than you expect. That's why I recommended the Catalina Aquarium light, which I have data from. A FishNeedIt light would give far less light.[/QUOTgetting
> 
> I am getting a quote on the one bulb 24 " & the 36" fixture from Catalina.
> I also wanted to clarify something you said.
> 
> 1. If I use the 36" mount 15 above top of tank
> 2. if I use the 24" mount 12 " above tank
> 
> I am also looking a the spiral CF as the location of the tank & light may be beneficial for more than one use, as the back of my favorite chair is in front of this tank. If I were to use say an architectural fixture like on a drawing board I could use it for back lighting or over the should lighting while doing my online stuff ( usually very early morning) in the dark and also
> I learned a lot from you Hoppy . It still blows my mind that less light above the tank is better than more light directly on top of the tank
> Thanks again and Happy Holiday to you Sir


----------



## LetsTalkTanks

read one below


----------



## LetsTalkTanks

hey guys, quick question. is the microlmols measured at the bottom of the tank or at the tank when determining the intestity of the par?


----------



## joyce20

so if was going to run 4 36" t-5 HO's 39w each for a total of 156w..... would the be enough for a planted tank in my 150g 72L"x24H"x18D????


----------



## Binxter

*question about this?*

i have a 55 gallon tank(21 inches tall with 4 inches of substrate). i have 4 26 watt t5NO bulbs. 2 colormax 2 daylight. the fixture sits directly on my tank. what kind of plants can i grow, or where does my system rate on this scale.i am fairly new to this but am doing ok.


----------



## Hoppy

LetsTalkTanks said:


> hey guys, quick question. is the microlmols measured at the bottom of the tank or at the tank when determining the intestity of the par?


The light intensity varies from top to bottom of the tank - highest at the top and lowest at the bottom. Since all plants start life at the bottom and need light the most then, I use the PAR at the substrate level to determine what light level I have. The charts give PAR at any distance from the light, so you could use the intensity at the top or middle of the tank if you wanted to.


----------



## Hoppy

joyce20 said:


> so if was going to run 4 36" t-5 HO's 39w each for a total of 156w..... would the be enough for a planted tank in my 150g 72L"x24H"x18D????


One T5HO bulb, with a good reflector and HO ballast will give you about 60-70 micromols of PAR at a distance of 21 inches (assuming you have 3 inches of substrate). That is so much light you have to use CO2 to avoid lots of algae problems. I assume your bulbs are in two rows across the top of the tank. If so, the rows should be about 8 inches or so apart to cover the whole substrate without getting way too much light. Or, if the two rows are close together, you can have the light about a foot above the top of the tank, and get around 40 micromols of PAR, which is all you really need. You may not have good reflectors, and some cheap lights don't even have HO ballasts. If that describes yours, you could even have too little light.


----------



## S&KGray

LetsTalkTanks said:


> hey guys, quick question. is the microlmols measured at the bottom of the tank or at the tank when determining the intestity of the par?


Usually measured at the substrate level. Dang, Hoppy beat me to it, and has a better answer. :icon_smil



joyce20 said:


> so if was going to run 4 36" t-5 HO's 39w each for a total of 156w..... would the be enough for a planted tank in my 150g 72L"x24H"x18D????


Depends on the type of T5HO fixture (ballasts and reflectors), the output can be highly variable between different ones. Again, see Hoppy's reply also :tongue:



Binxter said:


> i have a 55 gallon tank(21 inches tall with 4 inches of substrate). i have 4 26 watt t5NO bulbs. 2 colormax 2 daylight. the fixture sits directly on my tank. what kind of plants can i grow, or where does my system rate on this scale.i am fairly new to this but am doing ok.


Probably low light but depends on the reflectors in your fixture.


----------



## Hoppy

Binxter said:


> i have a 55 gallon tank(21 inches tall with 4 inches of substrate). i have 4 26 watt t5NO bulbs. 2 colormax 2 daylight. the fixture sits directly on my tank. what kind of plants can i grow, or where does my system rate on this scale.i am fairly new to this but am doing ok.


If that light is a Coralife (Aqueon) light or pair of lights, you have low light. With good CO2 you can still grow almost all of the usual aquatic plants, but they will grow slowly. Without CO2 you will be limited to low light plants only.


----------



## Binxter

its aqueon, there are 2 fixtures with 2 bulbs, one colormax,one daylight in each, i add bottled co2 as of now, tried the yeast way did not like it, causes a white film on the glass.im growing ambulia and crypto wendtii at rapid rates(i am giving away ambulia, with a warning not to introduce into the wild) altelanthrea growing very slowly(roots growing out of stems), and microsword and dwarf hairgrass are alive but not growing.if i were to invest in more light, should i get 2 more of the fixtures i already have or invest in t5ho?(with the ones i have, i work at a petstore and get them at a discounted rate)...where would be a good place to buy better lighting from?


----------



## joyce20

This is what i was looking at?









Coming with 78W Power Output in total, the latest 36" Aquarium Light offers both outstanding performance and modern design for your aquarium.
It supports 2 x 39W T5 HO Fluorescent Lamps, which is an pretty good choice for saltwater, reef, or freshwater tropical aquariums.

Features:

Brand New in Box Ready to Be Operated Upon Arrival
Internal Highly Efficient Ballasts
Standard T5 Sockets
German Aluminum Reflector for Maximum and Optimal Lighting Effect
Non-corrosive Powder Coated Aluminum Housing
Acrylic Shield to Protect the Light from Splashing
Well-ventilated Design with Thermovents on Both Ends of the Fixture
Flippable Brackets to Fix the Light onto the Tank
Suitable for both Natural Freshwater and Saltwater Aquarium
CE Certificated
Voltage: 110 V
Overall Dimension: 36"L x 4 1/3"W x 1 3/4"H

Package Content:

1 x 36"Aquarium Light Fixture
2 x 39W 6,700K T5 HO Fluorescent Lamps
2 x Flippable Brackets


----------



## joyce20

2 of them, side by side to cover the 72"


----------



## Hoppy

joyce20 said:


> This is what i was looking at?
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Coming with 78W Power Output in total, the latest 36" Aquarium Light offers both outstanding performance and modern design for your aquarium.
> It supports 2 x 39W T5 HO Fluorescent Lamps, which is an pretty good choice for saltwater, reef, or freshwater tropical aquariums.
> 
> Features:
> 
> Brand New in Box Ready to Be Operated Upon Arrival
> Internal Highly Efficient Ballasts
> Standard T5 Sockets
> German Aluminum Reflector for Maximum and Optimal Lighting Effect
> Non-corrosive Powder Coated Aluminum Housing
> Acrylic Shield to Protect the Light from Splashing
> Well-ventilated Design with Thermovents on Both Ends of the Fixture
> Flippable Brackets to Fix the Light onto the Tank
> Suitable for both Natural Freshwater and Saltwater Aquarium
> CE Certificated
> Voltage: 110 V
> Overall Dimension: 36"L x 4 1/3"W x 1 3/4"H
> 
> Package Content:
> 
> 1 x 36"Aquarium Light Fixture
> 2 x 39W 6,700K T5 HO Fluorescent Lamps
> 2 x Flippable Brackets


This should give medium light, as far as I can tell. But, you really need CO2 and good pressurized CO2 at that, for it to work well. I hope you are also dosing NPK and trace elements, because the plants need that either in the water or in the substrate or both.


----------



## joyce20

i havent gotten anything yet. I wanted to get some input on lights first. i have never done Planted before. I have only done Freshwater and Reef.

any Ideas on other (ideal) lighting for about the same price?


----------



## lobsterbib

Hoppy said:


> That is so much light you have to use CO2 to avoid lots of algae problems.


 I've been reading that on several of the lighting threads here. Does the higher CO2 concentration suppress algal growth? What's the mechanism?


----------



## exv152

I was thinking of using this LED for a 23 gal tank, total depth would be 45cm (or 17.7"). I calculated that would be approximately 90 PAR for the middle of the tank, on the substrate. Would this be considered high, med or low lighting? Also, this is a marine LED, would that work for a freshwater application?


----------



## Daximus

joyce20 said:


> i havent gotten anything yet. I wanted to get some input on lights first. i have never done Planted before. I have only done Freshwater and Reef.
> 
> any Ideas on other (ideal) lighting for about the same price?


Do you want a high maintenance setup? Or a low maintenance setup?

This matters when selecting lights. Light drives plant growth (I know, duh), but as they grow they will need nutrients, and if you have too much light you will need Co2, otherwise you will have a 125 gallon algae farm.


----------



## S&KGray

exv152 said:


> I was thinking of using this LED for a 23 gal tank, total depth would be 45cm (or 17.7"). I calculated that would be approximately 90 PAR for the middle of the tank, on the substrate. Would this be considered high, med or low lighting? Also, this is a marine LED, would that work for a freshwater application?



I would consider 90 PAR to be high lighting. It would work for a freshwater application, but might have a higher Kelvin (color temp) than most freshwater type lights which would result in a more bluish look that some actually prefer.


----------



## joyce20

i was wanting a low mantaince tank, and really dont want to run CO2 but if i have to then i would run some sort of DYI style. i will have some live plants but nothing that will require high light. the reason i ask is because i can get 

2 bulb T5 HO bulb set-up for 78w for only $49. i was going to get 2 of them to take up the 72". i cant seem to find anything scheaper.

Brandon


----------



## S&KGray

joyce20 said:


> i was wanting a low mantaince tank, and really dont want to run CO2 but if i have to then i would run some sort of DYI style. i will have some live plants but nothing that will require high light. the reason i ask is because i can get
> 
> 2 bulb T5 HO bulb set-up for 78w for only $49. i was going to get 2 of them to take up the 72". i cant seem to find anything scheaper.
> 
> Brandon



If that fixture can run with just 1 bulb then you should be in the low light range.

Search for threads about DIY with spiral CFL's, that might be cheaper.


----------



## S&KGray

Binxter said:


> its aqueon, there are 2 fixtures with 2 bulbs, one colormax,one daylight in each, i add bottled co2 as of now, tried the yeast way did not like it, causes a white film on the glass.im growing ambulia and crypto wendtii at rapid rates(i am giving away ambulia, with a warning not to introduce into the wild) altelanthrea growing very slowly(roots growing out of stems), and microsword and dwarf hairgrass are alive but not growing.if i were to invest in more light, should i get 2 more of the fixtures i already have or invest in t5ho?(with the ones i have, i work at a petstore and get them at a discounted rate)...where would be a good place to buy better lighting from?



I would try increasing CO2 first, make sure you have a decent fert regime, and if growth still isn't where you want it then think about more light.

If you decide you need more light then I would get 2 more of the fixtures you have if you can get them cheap. Especially if they can run with only 1 bulb in them, so you could increase to 3 bulbs per side at first and if you still want more then to 4 bulbs.


----------



## Hoppy

exv152 said:


> I was thinking of using this LED for a 23 gal tank, total depth would be 45cm (or 17.7"). I calculated that would be approximately 90 PAR for the middle of the tank, on the substrate. Would this be considered high, med or low lighting? Also, this is a marine LED, would that work for a freshwater application?


That light is virtually a spotlight. Note that even at 24 inches it produces only about a 6-8 inch diameter spot of light. I wouldn't even consider using it unless it was for a light mounted about 3 feet from the substrate.


----------



## S&KGray

Hoppy, that fixture he is asking about is the Marineland Reef-Capable LED fixture. I don't know how the light footprint looks exactly but I am pretty sure it wouldn't be a 6-8 inch diameter spot. I know of at least one person using it for planted tanks successfully.


----------



## Hoppy

The Marineland double bright light should work well for that tank. The word "LED", light emitting diode doesn't mean "light fixture using multiple light emitting diodes" - that's what fooled me


----------



## exv152

Hoppy said:


> The Marineland double bright light should work well for that tank. The word "LED", light emitting diode doesn't mean "light fixture using multiple light emitting diodes" - that's what fooled me


Thanks Hoppy. My intent is to setup a med-high tech setup with pressurized co2, ferts etc, but I wasn't sure if the light would be strong enough. 

Also, not sure about the different colours that are emitted from these marine-type fixtures, and whether or not it'll suit my planted tank.


----------



## pandacory

Regarding the updated t5ho chart, I am a little confused.

It is saying to half the output to get to t5no output, but in the previous chart 2 bulb t5no on a 12" tank is listed as medium, where 1 t5ho is too high.

Can you explain the difference?

I would like to use Ho light for a 12" tank I'm planning, since it is more efficient than no, with more bulb choices, but I want to stay in the medium light range and am limited to having the light on top of the tank.


----------



## S&KGray

Hoppy said:


> The Marineland double bright light should work well for that tank. The word "LED", light emitting diode doesn't mean "light fixture using multiple light emitting diodes" - that's what fooled me


True, I found out it was that fixture by using the url of the chart exv152 linked in his post. :icon_mrgr And yes the double bright version could work, the reef-capable version might need to be suspended above the tank.



exv152 said:


> Thanks Hoppy. My intent is to setup a med-high tech setup with pressurized co2, ferts etc, but I wasn't sure if the light would be strong enough.
> 
> Also, not sure about the different colours that are emitted from these marine-type fixtures, and whether or not it'll suit my planted tank.


The reef-capable light is very strong for a shallow tank like yours, like I mentioned above it may need to be suspended above your tank. You may want to go with the double bright instead as Hoppy suggested and still use CO2, plants will grow slower, but it will be easier to manage.


----------



## plantbrain

Hoppy, you might want some of the data from the ATI fixtures I have, they make the Tek look like the PC vs the T5 lighting curves.

At 24" I'm reading 140-200 umols etc. Which if you look at the T5 graph........is kicking its butt.


----------



## exv152

S&KGray said:


> The reef-capable light is very strong for a shallow tank like yours, like I mentioned above it may need to be suspended above your tank. You may want to go with the double bright instead as Hoppy suggested and still use CO2, plants will grow slower, but it will be easier to manage.


Thanks s&kgray, the fact that LEDs don't require new bulbs every 6-12 months and the fact that it uses considerably less power was what attracted me the most. I agree, I think it's too much light and the wrong spectrum of light as well. And I'm not sure if the double brights are bright enough for what I want to do.


----------



## Hoppy

plantbrain said:


> Hoppy, you might want some of the data from the ATI fixtures I have, they make the Tek look like the PC vs the T5 lighting curves.
> 
> At 24" I'm reading 140-200 umols etc. Which if you look at the T5 graph........is kicking its butt.


Since those ATI lights are dimmable, it makes a lot less difference that they produce very high light. You can always reduce the intensity easily.

The farther I go with this the more convinced I am that we now have such a variety of T5 lighting available, of such a wide range of cost and quality, that we really need to use data from specific lights to judge them. The FishNeedIt T5HO lights produce a small fraction of the light a Tek light does, and apparently the ATI lights produce much more than a Tek light. Inbetween those extremes are Hagen GLO, Nova Extreme, the various hydroponic lights, etc.

Lighting manufacturers should be providing this type of data for all of their lights. Marineland did so for their LED lights, to my surprise. But, Catalina hasn't done so, as far as I know, and it would be so easy for them to do it.

I know!! Let's get Congress to pass a law requiring the data 



pandacory said:


> Regarding the updated t5ho chart, I am a little confused.
> 
> It is saying to half the output to get to t5no output, but in the previous chart 2 bulb t5no on a 12" tank is listed as medium, where 1 t5ho is too high.
> 
> Can you explain the difference?
> 
> I would like to use Ho light for a 12" tank I'm planning, since it is more efficient than no, with more bulb choices, but I want to stay in the medium light range and am limited to having the light on top of the tank.


It is confusing to me too. This is an ongoing project, so as I get more data from different lights I change the various charts I have. Sometimes I miss changing some charts. Just remember, those charts are very general, and can only get you looking at a category of lighting that has a good chance of being what you need. I do have some charts for some specific lights, but nowhere near for even 10% of what's available.


----------



## demonr6

Contacted Catalina to see if they can help me figure out a light for my tank from their product line. Reading this made my head spin.. much like the CO2 thread. LOL


----------



## audioaficionado

Hoppy said:


> I know!! Let's get Congress to pass a law requiring the data


I'm sure they'll get on it asap, right after they pass a balanced budget :icon_mrgr


----------



## 5BodyBlade

A thousand apologies, but I just couldn't read through 41 pages of thread to find my answer so I'll post and hope. In what area would 2x39W T5HO 24" from the sub be with gloss white paint as a reflector? I read somewhere that white was comparable as a reflector as aluminum. I've been using it for quite a while and have good results. Just wondering where I'd be sitting in the chart.


----------



## galabar

So, I'm setting up a 20 H and I'm trying to choose between the following:

http://www.amazon.com/AquaticLife-Dual-Freshwater-Light-Fixture/dp/B002BH5QT0
http://www.amazon.com/gp/product/B000VK1A94
http://www.amazon.com/Coralife-08600-Aqualight-Fixture-24-Inch/dp/B002P9MFW0

The AquaticLife seems to have the best reflector (Coralife worst?). Thoughts on the quality of these and the amount of light expected?

Here is another option:

http://www.petcarerx.com/Catalog/ProductDetails.aspx?pid=20285&k=Db+Solarmax+HO2+Ho+T5+Strip

Which do folks prefer?


----------



## Buc_Nasty

http://www.amazon.com/Marineland-Do...?s=pet-supplies&ie=UTF8&qid=1326501316&sr=1-1


----------



## S&KGray

galabar said:


> So, I'm setting up a 20 H and I'm trying to choose between the following:
> 
> http://www.amazon.com/AquaticLife-Dual-Freshwater-Light-Fixture/dp/B002BH5QT0
> http://www.amazon.com/gp/product/B000VK1A94
> http://www.amazon.com/Coralife-08600-Aqualight-Fixture-24-Inch/dp/B002P9MFW0
> 
> The AquaticLife seems to have the best reflector (Coralife worst?). Thoughts on the quality of these and the amount of light expected?
> 
> Here is another option:
> 
> http://www.petcarerx.com/Catalog/ProductDetails.aspx?pid=20285&k=Db+Solarmax+HO2+Ho+T5+Strip
> 
> Which do folks prefer?


Here are a couple of other options to consider:

http://www.amazon.com/Zoo-Med-AquaS...h/dp/B0002DIRAU/ref=pd_sim_sbs_petsupplies_18

and the Marineland Reef-capable LED (probably need to suspend above tank for best coverage and not too much PAR)

http://www.amazon.com/Marineland-Ca...ch/dp/B00494NBPE/ref=pd_sim_sbs_petsupplies_8


----------



## Buc_Nasty

Haha we're not really helping him narrow the choices. 

Get some low light plants and some root tabs (try a petco bulb pack and maybe one pre-grown plant), and get the double bright LED. You'll thank me in 4 months when you have a cool looking aponogeton and dont have to spend tons of time and $$ trying to get rid of all the algae those strong lights are causing, and dont then consider going CO2 and fertilizer, then spend hours researching it, spend $300 on it, get sick of it after another couple months, then wish you had just gone double bright w low light plants. Also your electric bill will be a lot lower, and the double brights look amazing. (I've been through the process and this is my end result and its awesome haha)


----------



## Hoppy

5BodyBlade said:


> A thousand apologies, but I just couldn't read through 41 pages of thread to find my answer so I'll post and hope. In what area would 2x39W T5HO 24" from the sub be with gloss white paint as a reflector? I read somewhere that white was comparable as a reflector as aluminum. I've been using it for quite a while and have good results. Just wondering where I'd be sitting in the chart.


I missed reading this when it was posted. Sorry.

Your question can't be answered at all accurately. How much light you get depends on the reflector - you need to be able to see at least 2 reflections of each bulb in the reflector, to get roughly 2-3 times as much light as a bare bulb. And, the ballast needs to be a true HO ballast, driving the bulbs to the full 39 watts or a bit more. With that I can make a reasonable guess about how much light you have, if I also know if the bulbs are close together or 4+ inches apart. But, with a flat white painted reflector, I can only make a very crude guess about how much light you have - somewhere around 15-30 micromols of PAR, if the bulbs are close together. That is low light, and only if the ballast is a true HO ballast.


----------



## NyteBlade

I have a 20 gallon long, 30" tank with a 65 watt PC and probably a mediocre reflector. 

According to the chart, 1 single PC bulb (55-65 watt I assume?) about 4 inches above the tank is considered "low light". 

A 2x24 watt T5HO with reasonable reflectors would be considered "too high" lighting. 

Is that correct? Is the difference between a 65w PC light and a 2x24w T5HO on a 12" high tank would raise my light from "low" to "too high"? Or am I mis-reading the chart?


----------



## Hoppy

NyteBlade said:


> I have a 20 gallon long, 30" tank with a 65 watt PC and probably a mediocre reflector.
> 
> According to the chart, 1 single PC bulb (55-65 watt I assume?) about 4 inches above the tank is considered "low light".
> 
> A 2x24 watt T5HO with reasonable reflectors would be considered "too high" lighting.
> 
> Is that correct? Is the difference between a 65w PC light and a 2x24w T5HO on a 12" high tank would raise my light from "low" to "too high"? Or am I mis-reading the chart?


A 20 gallon long tank is about 12 inches high, with 2 inches of substrate, the top of the tank is only 10 inches from the substrate. At 14 inches from the light, the PC light is probably giving you low medium light, and the 2 x 24 watt T5HO, with virtually no reflector would give you high light. A Coralife 2 x T5NO light would give you low light, and a 2 x 24 watt FishNeedIt light would give you low medium light. (FishNeedIt "T5HO" lights run more like T5NO than T5HO.)


----------



## madness

galabar said:


> So, I'm setting up a 20 H and I'm trying to choose between the following:
> 
> http://www.amazon.com/AquaticLife-Dual-Freshwater-Light-Fixture/dp/B002BH5QT0


I have the AquaticLife 2 bulb T5HO fixtures on two different tanks - a 30XH (same as the 20H but just a lot taller) and on a 20" version on a 16G bowfront.

For a 20H the AquaticLife fixture would be great. Really almost too much light actually but it is a great fixture and since they include two bulbs but one of them is a roseate bulb it doesn't really seem as bright as using two daylight bulbs (which is a good thing in this case).

I would be really, really shocked if you couldn't grow any plant at all very easily and very quickly with the 24" AquaticLife T5HO freshwater fixture.

edit: feel like I should emphasize more that the 24" dual bulb T5HO from AquaticLife is a LOT of light (most likely too much light according to the charts) and that I do use various methods to cut down the intensity on mine (mostly I just use a lot of floating plants). The reason I would endorse the fixture is because I feel like it will definitely provide full high lighting for those who want it and the price and quality are solid. Definitely higher quality than the corallife/aqueon 2 bulb T5NO fixtures (which probably provide a more healthy/lower level of light).


----------



## raymond_h2002

I've got a hold of a PAR meter and did some measuring. I have some questions about lighting my 90g running 4x 54w teklights (8 hour cycle) 10 inches above the water, 30 inches above substrate. Tank runs on diffused co2 + EI Fertilization.
There's also a center brace that blocks light in the center third of the tank, and the light has an acrylic shield.

Measured PAR:
Substrate = ~90umol
1 inch below surface of water = 200 - 250umol

It looks like I'm over the ideal 50 - 60umol @ substrate. My bigger concern is whether 250umol near the surface is so much light that it destabilizes the tank? 

I see two solutions to this.
1) Wire meshing over the lights, which others have shown to reduce the light by ~40%
2) raise the lights another 6 - 12 inches.

I understand that Option 2 is ideal to reduce delta between the surface and substrate and would solve both my concerns. Option 1 is easier to implement, as I'm at the max height that my current hardware allows, which means I would have to drill into the ceiling to install hangers if I want to raise the light any more. Plus, the spillover at 12 inches annoys me enough as it is... raising it any more would be worse. 

If I choose to use the wire meshing, I'd estimate the intensity to be ~175 umol. Would that still be at disruptively high light levels near the top of the tank?


----------



## Hoppy

The ideal light source is the sun, since it is so far away the PAR at the surface and at the substrate is the same. Next best is a very bright light fixture mounted a few tank heights above the tank. That greatly reduces the spread in PAR from substrate to water surface, but isn't practical for many reasons. A compromise would be to hang the light one tank height above the tank, reducing the spread to 4 to 1 from water level to substrate level.

One more way to reduce the spread of PAR is to distribute the light source over the whole top of the tank - use lots of lower power LEDs for example. This also reduces the PAR at the water surface, because much of the light source doesn't affect any given square inch of water surface. (A square inch at the end of the tank gets no light from light at the other end of the tank.) Tube fluorescent lights somewhat reduce the spread, because light from one end of the bulb never gets through the water surface at the other end of the tank. And, any light not from directly over one spot travels much farther, so has a lower intensity.

Virtually all plants begin their growth at the substrate level, and the beginning growth is associated with starting the roots, converting from emersed leaves to submersed leaves, etc. So, I believe it is best to rate lighting by the PAR at the substrate, and that is all I have done. The next step is to monitor PAR at various places in the tank, accounting for shading by the higher plants, for plant density, and for difference in light input over the whole top of the tank. That would always depend on the individual tank.


----------



## starlin

i am setting up a low-tech planted tank and trying to decide on a t5ho light fixture.

have this one in mind..> 120cm.
http://www.theaquariumcompany.com.au/pages/products/category/lights-t5-high-output/

using 1x54 watt globe, the light would need to be 17-18 inches from my substrate? & which globe would be best?, life glo 6500k/aqua star 10,000k??

tank size is. 20h x 14w x 48l.

please correct me... point me in the right direction, currently, confused.:help:


----------



## madness

If you are talking about the two bulb fixture (with individual switches) that could be a great option. 

6500K bulb would be great. 10,000K might be OK as well.

I am far from an expert but when I see a bulb that is in the 6000-7000K range as an option that is what I usually settle on based upon what I have read/experienced.



starlin said:


> i am setting up a low-tech planted tank and trying to decide on a t5ho light fixture.
> 
> have this one in mind..> 120cm.
> http://www.theaquariumcompany.com.au/pages/products/category/lights-t5-high-output/
> 
> using 1x54 watt globe, the light would need to be 17-18 inches from my substrate? & which globe would be best?, life glo 6500k/aqua star 10,000k??
> 
> tank size is. 20h x 14w x 48l.
> 
> please correct me... point me in the right direction, currently, confused.:help:


----------



## madness

Hoppy: I just noticed the expanded charts and reflector comparisons in the original post.

Not sure how long they have been there and I just didn't notice them but they are definitely a nice addition.


----------



## starlin

ok, i will be getting this fixture with a Life Glo 6700k globe, with one globe off. so 1x54w 6700k.

http://www.theaquariumcompany.com.a...aqua-nova-t5-high-output-light-120cm-long-kw/

at what height above the substrate would be good, in my low tech planted tank? 14w x 48l x 20h.

with 3 inches of substrate, and the light directly on top of the tank would give me 17 inches. i can place it from 0-4 inches above the top of the tank, inside the hood. or if i need to give it more room, i could remove the top from my hood.

what would be an ideal height to place my light at? , for my low-tech planted tank, no co2. i want my plants to thrive.:help:


----------



## madness

My interpretation of the chart shows that 17" over the substrate (directly on top of the tank as you stated) is going to be too much light.

4" above the top of the tank would put you smack dab in the middle of medium lighting 50-60 micromol which is a range that should allow you to grow any plant out there (though some would require CO2 and heavy ferts regardless of light).

4" above the top of the tank (50-60 micromol) is very likely still too much light for the type of tank that you are planning to have. A single piece of window screening would probably drop it into the proper light range (though I don't have Hoppy's calculations on how much light is removed by window screen memorized or handy at the moment).

I am guessing that somewhere around 30 micromols might be a good light level for you.

If it was me I would raise the light all the way up in the canopy and just see what I got - with that one T5HO bulb you are unlikely to kill or hurt the plants. The problems will relate to algae not so much plant growth. If you get to fighting algae more than you want then try window screening and/or put in floating plants.

I actually use 2 bulb T5HO fixtures on my smaller low tech tanks (moss, java ferns, etc. pretty much like what you are doing) and it is WAY too much light but I just throw in floating frogbit and it grows to cover most of the surface and block out a lot of light. I don't have algae problems in these tanks.

Your useage might vary.

I think with this fixture though you are in a really good place where you have some flexibility and definitely can make the fixture work for you anywhere from low light to high light without too much trouble.

I think that if more people had fixtures like this (two T5HO bulbs but only using one of them at a time) that there would be a whole lot less algae issues that people had to fight.



starlin said:


> ok, i will be getting this fixture with a Life Glo 6700k globe, with one globe off. so 1x54w 6700k.
> 
> http://www.theaquariumcompany.com.a...aqua-nova-t5-high-output-light-120cm-long-kw/
> 
> at what height above the substrate would be good, in my low tech planted tank? 14w x 48l x 20h.
> 
> with 3 inches of substrate, and the light directly on top of the tank would give me 17 inches. i can place it from 0-4 inches above the top of the tank, inside the hood. or if i need to give it more room, i could remove the top from my hood.
> 
> what would be an ideal height to place my light at? , for my low-tech planted tank, no co2. i want my plants to thrive.:help:


----------



## daworldisblack

Hoppy said:


> The T5HO line on the first chart has been difficult to apply, because so many cheap T5HO lights with less than good reflectors are now available. To make it easier to estimate how much light you can get from different quality T5HO lights, try this chart:


Sweet Chart! Thanks Hoppy! Just had a question for anyone that may be able to help. I have a 24" dual T5HO Hagen Glo fixture - so it only has one parabolic reflector for both bulbs which people say ain't the best. So I am looking at the 'Fair Reflectors' line here. To achieve med light I can have my fixture anywhere from 18" to 23" above the substrate right? Aquarium footprint is 30" long by 12" wide by 16" high. Unless the fixture belongs to a different 'class' of reflectors - in which case, anyone with experience there? Thanks!


----------



## Hoppy

I haven't seen much PAR data for Hagen GLO lights, but from what I have seen, it doesn't have a very good reflector. Assuming it is a fair reflector, you would get medium light with it located about 13-17 inches from the substrate. So, if that 16 inch high tank has 3 inches of substrate, the light would be medium with it sitting on top of the tank up to 4 inches above the top of the tank.


----------



## Rev_jim_jones

The Hagen glow Reflector is more on the line of the upper level of Poor/lower level of fair...


----------



## Jeff5614

Rev_jim_jones said:


> The Hagen glow Reflector is more on the line of the upper level of Poor/lower level of fair...


It may be poor but I used one for years. It will grow any plant you want. The tank in my sig used a 2x54 Hagen Glo fixture.


----------



## Matt.L

*Newbie!*

Can i just check with you please?.....

I am a total newbie and I am in the middle of setting up my new tank 

ok so I have a 55"x16" with a height of 24" 

Bulbs = 2 x T5HO one of these is 18000k the other 6700k

The height from substrate to bulbs is 23" 

The bulbs are in a enclosed in a light colour oak hood with no reflectors and the bulbs will be about 6" apart.

Im making this low to med light? is this right? and if so would you say I could use another bulb? I have jbl co2 unit that will be linked with the lights.

Please help 

Thanks,

Matt.


----------



## Hoppy

I think you have low to low medium light, too. If you added another bulb, also with no reflector, you should get about medium light. CO2 will be very desirable with that much light.


----------



## jmspaggi

Hi Hoppy,

Can you recommand me a PAR meter? 

Thanks.


----------



## 5BodyBlade

This the light I purchased.
http://www.marinedepot.com/36_Inch_...quaticLife-AK01138-FILTFIT56U-AK01140-vi.html
Very happy with it. Great look and all my plants are doing well. Glandulosa has never been better. Thanks for the info Hoppy.


----------



## Matt.L

Matt.L said:


> Can i just check with you please?.....
> 
> I am a total newbie and I am in the middle of setting up my new tank
> 
> ok so I have a 55"x16" with a height of 24"
> 
> Bulbs = 2 x T5HO one of these is 18000k the other 6700k
> 
> The height from substrate to bulbs is 23"
> 
> The bulbs are in a enclosed in a light colour oak hood with no reflectors and the bulbs will be about 6" apart.
> 
> Im making this low to med light? is this right? and if so would you say I could use another bulb? I have jbl co2 unit that will be linked with the lights.
> 
> Please help
> 
> Thanks,
> 
> Matt.





Hoppy said:


> I think you have low to low medium light, too. If you added another bulb, also with no reflector, you should get about medium light. CO2 will be very desirable with that much light.


 
Thank-you for your reply!

Ok now I'm a little concerned because I am hoping to eventually keep discus along with my plants and am trying to balance both needs if this makes sense.. 

As you are probably aware discus do not like bright light as they have big eyes and cannot close them hence no reflectors.
So bearing that in mind do you think I should fit a good reflector or just go with the extra bulb? I can't make my mind up on which would be best for both. I will plant to create sheltered areas for the discus and plants will be first as I don't plan to add discus until everything is right for them and the plants are well established. I am making this a little hard for myself as I would like to keep more than just low light level plants. 

I'm guessing I may have purchased the wrong kind of lighting to start with but it's going to have to work.

FYI I'm using Hagen Glo

Your take please would be much appreciated.

Thanks again, 

Matt.


----------



## Hoppy

Matt.L said:


> Thank-you for your reply!
> 
> Ok now I'm a little concerned because I am hoping to eventually keep discus along with my plants and am trying to balance both needs if this makes sense..
> 
> As you are probably aware discus do not like bright light as they have big eyes and cannot close them hence no reflectors.
> So bearing that in mind do you think I should fit a good reflector or just go with the extra bulb? I can't make my mind up on which would be best for both. I will plant to create sheltered areas for the discus and plants will be first as I don't plan to add discus until everything is right for them and the plants are well established. I am making this a little hard for myself as I would like to keep more than just low light level plants.
> 
> I'm guessing I may have purchased the wrong kind of lighting to start with but it's going to have to work.
> 
> FYI I'm using Hagen Glo
> 
> Your take please would be much appreciated.
> 
> Thanks again,
> 
> Matt.


You are concerned, I am confused! Hagen Glo lights have reflectors, just not very good ones. Did you remove the reflectors and mount them in a hood minus reflectors? And, are you considering installing the reflectors? If so, I think you might still have low to medium light, since the light from the two reflectors would not add together very much, with them separated that far. But, the not-so-good reflectors would keep the light from being too intense, too. It would probably increase the light but I suspect it wouldn't increase it enough to get into medium light. That is good, not bad!


----------



## ryc120

I have a Hagen Glo 24" 2 T5HO (24w per bulb) w/original reflectors sitting on top of the tank - 29 gallon (16" height above substrate)
Based on the graph I have medium light with the stock reflectors, but on the chart I get "too high" of light because the light fixture sits on top of the tank.

Which do I have? Too much light, or low/medium light?


----------



## Hoppy

jmspaggi said:


> Hi Hoppy,
> 
> Can you recommand me a PAR meter?
> 
> Thanks.


The only one I know of that is within a reasonable price range is the Apogee Quantum meter, http://www.apogeeinstruments.com/quantum/mqpricing.html I believe all PAR measurements made by planted tank keepers have been made with this. (MQ-200) Another option is to buy just the sensor, and use a digital millivoltmeter as the readout for it. But, those meters tend to be pretty expensive too.


----------



## Matt.L

Hoppy said:


> You are concerned, I am confused! Hagen Glo lights have reflectors, just not very good ones. Did you remove the reflectors and mount them in a hood minus reflectors? And, are you considering installing the reflectors? If so, I think you might still have low to medium light, since the light from the two reflectors would not add together very much, with them separated that far. But, the not-so-good reflectors would keep the light from being too intense, too. It would probably increase the light but I suspect it wouldn't increase it enough to get into medium light. That is good, not bad!


 
Thanks again for your reply and for your help.

I must tell you that my hagen glo lighting set up did not include reflectors here is a link to what I have purchased. However the reflectors are available to purchase separately.

http://www.123aquatics.co.uk/produc...nits/hagen-glo-t5-twin-starter-unit-1568.aspx

The unit I have is the twin 54W version it comes with all fittings to connect the bulbs to hood (bulbs sold separately of course) 

I could put the bulbs as close together or as far apart as I like so I am looking for your recommendation because I am confused as well.

Right now I'm thinking I'll purchase a third bulb which means another lighting unit (single). 

Thanks,

Matt.


----------



## jmspaggi

Hoppy said:


> The only one I know of that is within a reasonable price range is the Apogee Quantum meter, http://www.apogeeinstruments.com/quantum/mqpricing.html I believe all PAR measurements made by planted tank keepers have been made with this. (MQ-200) Another option is to buy just the sensor, and use a digital millivoltmeter as the readout for it. But, those meters tend to be pretty expensive too.



Perfect, thanks a lot. 

I will think about buying it. My water level is 38" so I really want to be sure I still have 50 PAR at the bottom...


----------



## audioaficionado

Make sure to spend the extra bux and get the one with the 2 meter sensor extension cable.


----------



## jmspaggi

audioaficionado said:


> Make sure to spend the extra bux and get the one with the 2 meter sensor extension cable.


oh, yes, no choice. I want to measure the PAR when the tank is full, so I will have to take this one. But thanks for warning me.

Now, the question is, do I want to put $500 on a PAR reader... Just to bad we can't rent them...


----------



## Tenor1

Gosh Jmspaggi, I had no idea q PAR meter costs that much. Our local plant club has one that we check-out on loan. I haven't borrowed it because I don't know what the numbers mean, thus my post just above yours.


----------



## Red-Tide

I've read several pages up front, skipped to the back and skimmed several middle pages of this thread.
It's great data and I have questions. 

I'm an old SPS guy so for me, the more light the better. I'm learning something new here.

Here's where I get wonky.
How does length affect this? I'm working on a 125 gallon tank. Doesn't that change anything?
18 inches deep. 24 tall. 

The guide suggests 2 T5HO would give me medium lighting for that depth/top to bottom. I could get 2 sets of 2x36 to cover the length of the tank. That's 4 bulbs. Am I at too much light at this point or since this is a larger tank, I'm good?


----------



## Hoppy

Imagine putting a divider in the middle of the tank, so each half of the tank is lit by the 3 foot bulb above it. Surely the PAR would be the same with or without the divider. But, the greater the distance from the bulb, the more the length matters. I don't have data to figure out just how much it matters, so it simplifies things to assume the length only affects how much of the tank gets light. I did have enough 2 foot, 4 foot and 6 foot bulb data to see that when those are over proportionate tanks, the PAR is very nearly the same for each one at the same distance.

EDIT: I did some more thinking about this subject, and realized that the reason why fluorescent bulb length doesn't affect the PAR, which means why a 40 watt T12 and 20 watt T12 produce the same PAR at the substrate is because of the fact that light reflects off of water at angles greater than the critical angle.









This also explains why a hanging light will cause the PAR near the ends of the tank to be less than in the middle of the tank, even though some additional light comes from light reflected off the ends of the tank. And, it explains why the drop in intensity is only approximately proportional to one over the square of the distance from the bulb. (The drop in intensity is less than the inverse square "rule" would predict.)


----------



## Red-Tide

Thanks for chopping up the obvious for me, Hoppy. I hadn't looked at it that way.

I appreciate the work you've done here. Being out of the hobby and coming back, I knew lighting was always flush with options and can get expensive. 

You've boiled it down nicely. Now I just need to resist the urge to go super bright and get something simple from HomeDepot. 

Cheers!


----------



## Hoppy

Red-Tide said:


> Thanks for chopping up the obvious for me, Hoppy. I hadn't looked at it that way.
> 
> I appreciate the work you've done here. Being out of the hobby and coming back, I knew lighting was always flush with options and can get expensive.
> 
> You've boiled it down nicely. Now I just need to resist the urge to go super bright and get something simple from HomeDepot.
> 
> Cheers!


I found that a tank full of BBA, and requiring twice weekly pruning, did all it took to help me resist the urge. I no longer feel that urge.


----------



## Hoppy

For those interested, I added more information to post #636 above. Light sure can get complicated.


----------



## madness

Red-Tide said:


> Thanks for chopping up the obvious for me, Hoppy. I hadn't looked at it that way.
> 
> I appreciate the work you've done here. Being out of the hobby and coming back, I knew lighting was always flush with options and can get expensive.
> 
> You've boiled it down nicely. Now I just need to resist the urge to go super bright and get something simple from HomeDepot.
> 
> Cheers!


Definitely don't need reef level lights.

Save the cash and get a good pressurized CO2 system instead.


----------



## jmspaggi

Hi Hoppy,

One more question for you regarding the lights...

I asked you month ago about my tank. It's a 38" deep tank. 4" of substrate, so water level is 34". 

I built the tank, and it's ready for the lightning. I bought 8x3' Tek reflectors with the T5HO.

Now I'm wondering about the height I should put the lights from the water.

I have 3 options. And one constraint: My wife.  She prefers it to be as low as possible because I already took to much place with the tank. But she will still understand if I have to put the lights on the ceiling.

Based on what you said above, and since my tank is 6 feet large, I should virtually place it at 6*0.6=3.6' from the water. This is more than what I have. I have 3' only.

So my first option is to place the lights as close as possible to the water. 
Second option is to place the lights at about 11" from the water, just to have enough space to jump into the water.
Third option is to place the lights as high as I can.

The closer the lights are to the water, the harder it will be to access the tank, but what I'm wondering is, what's the impact on the performances/maintenance/plants?

If I place the bulbs very close to the water, the PAR at the surface is going to be way higher than the PAR at the bottom. Will that make plants trying to go too quickly on the surface? Will that help growing algae? So will that add more maintenance to the plants? Also, since there will be "only" 4 lines of lights, will that mean that some area of the water will not receive lights? (See configuration here: http://www.plantedtank.net/forums/lighting/149012-light-36-deep-aquarium.html#post1524154 )

From what I understood, for the plants, the higher the light is, the better. But what's the impact to lower it?

Do you have any recommendation?

Thanks.


----------



## Hoppy

The first goal is to get the PAR that is appropriate for the plants, and the amount of work you are willing to do. With the three bulbs side by side, you should get about 40-50 micromols of PAR with the light sitting on top of the tank. If you raise it much higher you won't get adequate light at the substrate. In order to have the light high above the tank it has to be bright enough to still give you enough light at the substrate. With a 3 bulb T5HO light it isn't bright enough to do that. That makes the other questions moot.


----------



## jmspaggi

sorry, I might have not given the details correctly.

What I have is 8 x 36" T5HO. Installed like here: http://www.plantedtank.net/forums/lighting/149012-light-36-deep-aquarium.html#post1524154 following your recommandations. And not just 3 x T5HO.










Does it change the conclusions?

I can add more if required. The number of bulbs is not a constant. I just want to have good results.

Thanks.


----------



## madness

Even with a fourth bulb the tank is so tall that is seems like you will need to either place the fixture on the top of the tank or create a hanging light fixture that allows you to hang it only a few inches off the top of the tank but then be able to use the fixture to raise it up in order to work on the tank.

There are threads here about how to make your own light hanging rods using EMT or metal electrical conduit piping.

Here is an example of someone's thread where they did the hanging light fixture themselves to give you an idea. You would not need such a tall one.

http://www.plantedtank.net/forums/tank-journals/163954-mahkos-iwagumi-ohko-stone-journal.html

Not sure what you would need to do to hang the fixture (fixtures?) if you have multiple fixtures.


----------



## jmspaggi

I'm fine with the fixture, I should be able to find a way to build that, but I thought it was better to have the lights as high as possible 

So is it better to have the bulbds by 3 (instead of by 2) and place them higher? Or better to keep them by 2 and place them as close as possible of the water? I can place them at about 2" from the water with no issues...

Thanks for your comments.


----------



## madness

jmspaggi said:


> I'm fine with the fixture, I should be able to find a way to build that, but I thought it was better to have the lights as high as possible
> 
> So is it better to have the bulbds by 3 (instead of by 2) and place them higher? Or better to keep them by 2 and place them as close as possible of the water? I can place them at about 2" from the water with no issues...
> 
> Thanks for your comments.


I would say go with the set-up you indicated earlier that Hoppy suggested.

If you put them right on the top of the tank you should definitely have enough light to grow whatever plants that you want. Use whatever mounting legs might have come with them (that typically raise them an inch or two).



It might just be a little TOO much light which will make you have to fight with algae a little more.

With a big tank and a lot of lighting (both of which you have) it can just be REALLY helpful to be able to adjust the height of the light easily in order to 'dail in' the tank or balance it more easily.


----------



## jmspaggi

madness said:


> If you put them right on the top of the tank you should definitely have enough light to grow whatever plants that you want. Use whatever mounting legs might have come with them (that typically raise them an inch or two).


It's a wood home made tank, and home made lightnings  I just bought the reflectors, the ballast and the bulbs. So I have to build the top and can place the light at the exact distance I want / have too.




madness said:


> It might just be a little TOO much light which will make you have to fight with algae a little more.
> 
> With a big tank and a lot of lighting (both of which you have) it can just be REALLY helpful to be able to adjust the height of the light easily in order to 'dail in' the tank or balance it more easily.



And I'm afraid about algae because I don't want to spend my days to clean them... So finnaly I will go the the adjutable option. I will build something wich will allow me to move the lamps from 1" to about 24" from the water...

I will also probably buy a PAR meter, and will all of that, I might be able to find a good configuration 

Thanks.


----------



## GxneFishing

Ok guys Sorry for my lenghty post but this stuff is driving me mad and maybe my little bit of leg work may help some others.
My current tank:
36 Gal bowfront corner tank 18" to substrate
lighting:
Stock hood 2x 15w t8 
DIY hood 2x 13w 6500k 2x 26w 6500k CFL's 4" 

10 hrs a day problem is the above fisxture I built I did for my 20 gal tall. So i Run that light on the 20 gal during the day then move it over to the 36 at night. Its becomming a hassle. I just want something for the 36 but im not happy with the DIY one I built. for either tank.

This is my second planted tank. I am sick of googling, trying and just plain stressing over lighting for this tank. I didn't want to start a new thread on something thats possibly answered elsewhere but ive been searching for over a month and haven't found everything I had questions about. There are so many opinions on good quality, bad quality, waste of money and so on. I have gathered everything I had an intrest in and plan to put it in one post. Lighting might be easy for some but I have lost sleep over it. Im probably making more of it than it really is though.

Im looking for med, low light. why? I don't know. I figured if im gonna do it I might as well do it right. buy/build a fixture I can expand with. I believe I can grow low light plants at high light levels.
Im currently growing low light plants and they appear to be growing . Bacopa salzmannii, Anubias lanceolata ,Bacopa monerieri, Lindernia sp Hygrophila difformis must be pretty forgiving plants!
Im not currently running any CO2 because I don't have a need for it at this time. but if I create that need ill be glad to try a DIY system at first. A wise man once said, 
Don't assume that all T5HO lights are equal. They aren't. Some have very poor reflectors, underpowered ballasts, and give far less light than you expect.
Tonight I bought 3x 8 1/2" Bayco Clamp lights and 3 26w 6500k bulbs.
$37.00 for the bulbs and clamplights. 
They are just sitting on the glass top at the moment. The 26w bulb is to long so the fixtures dont sit flat on the glass. And I think its ugly, The three lights look good to me on a straight tank but this deformed cocked sideways triangle isn't cutting it for me. It does seem to light the tank uniform the back is actually visible.

http://www.plantedtank.net/forums/m...04086675192-1051234981-2734795-35815183-n.jpg



This is what I have been looking at: I dont believe I can put links to everything so I think ill just do a brief explanation of the products.

The useable area for the light( where the glass was designed for a light) is 24" x 6" or so im looking for 24" of lights.


First up was the simple easy localaly available product, If you call my LFS 80 miles away being local: Petsmart
24" Aqueon T5 Dual light fixture 59.99
I haven't seen to many people have to many nice things to say about the quality of this fixture. I don't believe it will produce enough light for even medium light in my tank as it comes in the box. I haven't seen this fixture out of the box yet but im willing to bet the bulbs aren't 24" long. again I havent seen much on this fixture.

30" Aqueon T5 Dual light fixture 69.99
This being 30" long should fit considering I have 24" of glass and 32 or so inches to the edge of the tank depending on how it sits on the top.


The great looking but im sure to good to be true: 39.99
Odyssea Dual Pro 24" 
Free Bulbs in each unit: 1x 24W 10000K daylight bulb, 1x 24W True Actinic bulb. I would possibly have to replace both of the bulbs. Again I haven't heard anything good from someone on this fixture.wattage suitable for low light, I recall seing people before ask about these fixtures and got responses along the lines of , it would make a light up skateboard.











Z00 Med 2x 24w T5 HO 24" $55.00 NO BULBS 
Bulbs $30.00
$85.00
Seems this wattage is ideal for low light plants, it has a so so reflector, again not to much on this forum about it.









Coralife Aqualight HO T-5 Dual Lamp Aquarium Light Fixture 108.00
Now that we are talking a 50.00 price increase are we getting to the decent equiptment? This fixture comes with 2 bulbs but I believe they are both crap for planted tanks. so add another 30 bucks for lamps. but coralife name pops up alot in peoples posts.









And my last and final attempt until I get introduced to 10 more fixtures, ideas and options. Im open to everything logical were all on a budget but somethings arent worth cutting back on.

An A H Supply kit in my exhisting canopy.. I believe 70.00 for my 24" Hood 

How about building a t5ho fixture? Cheap ballasts? any ideas?? Cheap bulb sockets?? TEK 2 reflkector? Ice Cap reflector? Generic Reflector? How Do I get 2 bulbs and a reflector in a hood thats only 5 1/4" wide? it seems some of the reflectors I looked at were 3" wide :/ 
Aquaticlife 24" shipped 25.67 x2
Sunblaze 48" shipped 23.46 shipped
Glo 24" Shipped 24.00 x2
Icecap 47" 36.50 shipped
TEK II 24" 25.00 x 2 shipped
clips for an extra 8.00
so already with a reflector I seem to be halfway into the price of a comnplete fixture... Is there something im missing??


----------



## Hoppy

Since those three bell shaped "work lights" with 26 watt CFL bulbs seems to work well, why not spend your energy making them look good and stick with them? You can hang the light by their electric cords, so the bulbs don't contact the cover glass. You can paint the reflectors with glossy spray paint. You can use a hanger bar across the top, hang them separately from the ceiling, or even make a wood enclosure to hold the reflectors, with the enclosure sitting on the tank. A major advantage they have is the ease of changing the amount of light you get by just replacing the bulbs.


----------



## FooDog

Hey Hoppy, I'm getting a higher PAR reading from the fixture when the sensor is in water. Almost double @ 12" deep! Is this because the water is acting like a reflector? If that is true, would a deep tank have a lower PAR reading on the bottom in comparison to a reading outside of water (due to water reflecting light near the surface decreasing the amount of light hitting bottom)? Just trying to better understand these readings. Is it safe to say I can double the reading I get outside the water to equate to what PAR would be inside an aquarium? I'm in the market for a new light and I don't want to ask my LFS if I can test all their models suspended over their aquarium along with putting my hand and apogee in their tanks, lol. I'd rather keep it dry, and maybe double the reading I'm getting from their fixture to estimate what it would be inside an actual aquarium.


----------



## Hoppy

The limited testing I have done gave me around 10-20% more PAR with water in the tank than without water. I doubt that it could double the PAR. That happens for two reasons: first the air to water interface tends to focus the light a bit - the rays are bent towards the vertical, which increases the PAR. Second, the glass outer surfaces, the glass to air interface reflects a lot of light back into the water. This doesn't have any effect I could see at the center of the tank, but the drop off in PAR near the sides was a lot less, and in the corners it could even be as high or a bit higher than in the middle. This effect depends on the glass being very clean, and no paint on the outside of the glass. (This effect was first noted and reported by someone other than me.)


----------



## braddiamond

Tank. 48 x 18 x 22 72g bowfront
Pressureizd co2
Dry ferts 50% weekly water changes
Well planted tank with fish and inverts
I presently have a 4 bulb cf corallife fixture 55x4 watts It gets really hot even with the fan.
I need to work on removing some heat from this tank. I don't want to move my current light higher or mount it from ceiling. I like the look of the fixture on legs on top of the tank.
I read thru the chart and I just want to see if you can confirm that a t5ho with 2 54w bulbs is right for my setup. From what I read the catalina fixture has good reflectors. The chart says this is med lighting. But my assumption is these reflectors make up the difference.
My goal is high light, lowest heat possible and low power consumption.


On a side note the only other equipment that I have that puts out heat is my mag7. Any idea what this does?

Please advise...thanks for your time.


----------



## Hoppy

braddiamond said:


> Tank. 48 x 18 x 22 72g bowfront
> Pressureizd co2
> Dry ferts 50% weekly water changes
> Well planted tank with fish and inverts
> I presently have a 4 bulb cf corallife fixture 55x4 watts It gets really hot even with the fan.
> I need to work on removing some heat from this tank. I don't want to move my current light higher or mount it from ceiling. I like the look of the fixture on legs on top of the tank.
> I read thru the chart and I just want to see if you can confirm that a t5ho with 2 54w bulbs is right for my setup. From what I read the catalina fixture has good reflectors. The chart says this is med lighting. But my assumption is these reflectors make up the difference.
> My goal is high light, lowest heat possible and low power consumption.
> 
> 
> On a side note the only other equipment that I have that puts out heat is my mag7. Any idea what this does?
> 
> Please advise...thanks for your time.


A 2 bulb T5HO light, with the bulbs close together, would give you too much light. But this one, http://www.catalinaaquarium.com/store/product_info.php?cPath=71_197&products_id=1842 with the bulbs well separated should work fine, and give you reasonably uniform light, about 40 micromols of PAR, over the whole substrate. (Using the legs the light comes with.)


----------



## braddiamond

Thanks a lot. I just called and Jim is a great guy. He is going to use the perforated fixture which will help me with my heat issues. He said this unit is like running 3 bulbs b/c of the reflectors, which acording to the chart gets me into the HIGH zone, which is what i want.
Should i get the 2 6500k bulbs? 
Also what are you favorite bulbs when these go?

Any idea what kinda heat a submerged mag7 puts out?

Thanks again


----------



## SinisterSOB

Hello,

After reading through about half the posts I'm still a little lost.

My tank is 125g
20" deep
2" of substrate
No substrate fertilizer (because I'm a newb)
Heavy planted (vals, swords, sagittaria subulata)
numerous small South American cichlids
I dose with Excell and Flourish once every two days

I have a industrial lighting hood that is currently housing 2 T5HO lights. The fixture is hanging from the ceiling, and the bulbs are roughly 6" from the top of the tank.

From the charts on the 1st and 2nd page, my current set up is producing a High amount of light, even though I'm just under a watts per gallon?

The plants I have in my tank are supposed to do better with medium light, so if I raise the lighting fixture another 6" they should start to perk up?

My nitrates are constantly at 0ppm, and I battle yellow nasty leafs all the time...Not so much algea, but yellow leafs are my bane.

Fish are super simple to take care of, but plants...damn I wish I would've payed attention in science class.

Any help in understanding my lighting situation is greatly appreciated.


----------



## Hoppy

Lighting is just the starting point - you also need to provide the nutrients the plants need to grow at the rate the lighting is driving them to. That means dosing a source of nitrogen, phosphorous, potassium, trace elements (including iron), and carbon in sufficient amounts. Read the sticky in the fertilizing forum for details.


----------



## braddiamond

Hoppy, can you please help me out with these 2 final questions.
Should I get the 2 65k catalina bulbs? or a 10k/65k combo....from visual and a 
performance perspective.

Or just keep these as a backup and buy 2 other bulbs, what are you favorite bulbs?

Thanks


----------



## audioaficionado

Here you go Mr. Diamond:
http://akvateka.hu/wera/garnela/akvariumfenyek/index.html


----------



## Regenesis

The problem I have with that chart is it assumes all lighting is the length of the tank and that nobody uses shorter tubes.. ?


----------



## Rainer

Good point, especially in 30" tanks like the 29g. But the majority of the tank receives full lighting, so we go with that.


----------



## Hoppy

It doesn't matter if the fluorescent tubes are the same length of the tank or shorter, or longer. Shorter tubes just light less of the substrate, so you don't get uniform light. Longer tubes just waste light in spillover. You could light a 6 foot long tank with a single 2 foot long fluorescent tube in the middle, but you would get the PAR values listed only in the middle foot or so directly under the light. Put 3 of those 2 foot tubes in a row and you light the whole length of the tank.

If you hang the light 4 feet above the top of the tank you will get different PAR readings for different length tubes. But, that isn't how people light aquariums. For heights above the top of the tank that are a lot less than the length of the tank, the tube length doesn't change anything except how much of the tank gets uniform light.

This may help illustrate why this would be true.


----------



## vincenz

Been learning slowly through your posts Hoppy, and you're an asset to TPT. I haven't seen much from you regarding metal halide lights though-- do you not play around with them much?

I ask because I'm looking to make a 36x36 low-tech square tank, and want to hang a MH instead of tubes over the middle of it. The tank itself will only be 14" high. I want the light to hang 4 feet (48") above the tank. It sounds high, but after the tank is put on the stand, it will only stand 36" tall (so around waist level) and I don't want the light fixture to be in my face when I walk up to the tank. 

Now, I understand that a 70W MH at 2 feet above the tank is considered low light. So at 4 feet, this would be close to useless, correct? If I switch to a 150W MH at 4 feet above the tank, would you happen to know what kind of light I should expect? How about spillover? I could construct some shades to direct the light down further plus shade some of the room.

Heat aside, would this not be doable? Also to consider is that the tank will be situated in the corner of the room, right in front of 4 vertical windows (I know, complicated). Any tips? Should I stick with the 70W or go for the 150W? :icon_surp


----------



## Hoppy

I have never seen a good reason to use MH lights, so I have done nothing regarding them. I don't know how much PAR you get with one, nor much of anything else about them.


----------



## audioaficionado

Reef keepers might know more on MH PAR values. There are pendant LED arrays that can put out the same or greater PAR as MH.


----------



## brooklynfishman

So Hoppy, In refference to my other post about CO2, you are saying that I should have 2 or 3 T5HO bulbs ontop of my 24 inch deep tank? (fixture is about two inches above the tank.

Right now I am using 4 for 10 hours with all 8 bulbs for a 3 hour burst.

Could this be the reason I am having trouble maintaining my CO2 levels perhaps?

This could answer why my plant growth is SOOO compact. I thought that they were just not growing that fast...


----------



## sundragon

Hi Hoppy,

I'm relatively new to planted tanks and my tank that's about 6 weeks old has an expected algae bloom. the tank is 21" tall.

I had suspended my 4xT5HO 39w 6500k Aquaticlife fixture with bulbs on a hanger that's about 4" above the water and 18" above the substrate.

If I understand the chart in the beginning of this thread it was too high light.









I pulled the light up and it's now 11" above the water surface and ~28" above the substrate. Is this enough space to provide high light?

I can now focus on getting the photo period set properly - 8 hours with a 3 hour burst of both banks.


----------



## Hoppy

Sundragon, look at the next to last entry on that chart, which is for bulbs 28 inches from the substrate.


----------



## sundragon

Hoppy said:


> Sundragon, look at the next to last entry on that chart, which is for bulbs 28 inches from the substrate.


First, thanks for the response  

But I'm a little confused now 

Isn't my setup closest to the 4th line from the bottom of the chart? 20" tall (my tank 21") with a light ~12" (my light 11") from the surface?

I understand the second to last line represents a 28" distance light to substrate but isn't the light is much closer to the tank and more intense?

I was shooting for medium/high light. Do I need to increase the height another 4" to make it 32"?

Can you please explain the difference so I understand properly?


----------



## Hoppy

Light intensity falls off proportional to the distance squared (if the light is twice as far away the intensity is 1/4 as much). It doesn't matter if there is water or air between the light and the sensor measuring the light intensity. All the water does, for tank heights we use, is slightly focus the light, causing a higher intensity, and cause the glass walls of the tank to reflect light back to the substrate, also increasing the intensity. The total of those two effects is around 10-20%. So, it is the distance of the light to the substrate that is significant, not the distance of the light to the water.


----------



## sundragon

Hoppy said:


> Light intensity falls off proportional to the distance squared (if the light is twice as far away the intensity is 1/4 as much). It doesn't matter if there is water or air between the light and the sensor measuring the light intensity. All the water does, for tank heights we use, is slightly focus the light, causing a higher intensity, and cause the glass walls of the tank to reflect light back to the substrate, also increasing the intensity. The total of those two effects is around 10-20%. So, it is the distance of the light to the substrate that is significant, not the distance of the light to the water.


Understood completely - Thanks 

Hiked the light up another inch this morning - I'll hike it another three tonight to make it 32" and wait a week to see how the algae farm is doing :icon_eek:

I'm going to try to borrow a PAR meter from my aquatic plant group to fine tune the measurement.


----------



## Doc7

Have you considered (or are you even able) going down to 2 bulbs? Then you could keep the light mounted somewhat lower if that is your preference...

Though on the other hand the farthest away from the tank you can get while having non-bothersome spillover and get 40-60 PAR, the more even lighting throughout the level column (ie, the sun is so far away that the inverse square law is meaningless for 2 feet of water..)... So as far as evenness of PAR top-to-bottom in your water column, the more bulbs the better, farther away from tank..

But might be easier on your electric bill and room aesthetics to just run 2 bulbs??

Sent from my BlackBerry 9650 using Tapatalk


----------



## sundragon

Doc7 said:


> Have you considered (or are you even able) going down to 2 bulbs? Then you could keep the light mounted somewhat lower if that is your preference...
> 
> Though on the other hand the farthest away from the tank you can get while having non-bothersome spillover and get 40-60 PAR, the more even lighting throughout the level column (ie, the sun is so far away that the inverse square law is meaningless for 2 feet of water..)... So as far as evenness of PAR top-to-bottom in your water column, the more bulbs the better, farther away from tank..
> 
> But might be easier on your electric bill and room aesthetics to just run 2 bulbs??
> 
> Sent from my BlackBerry 9650 using Tapatalk


I run it for 8 hours on 2 bulbs with a 3 hour burst of all 4 bulbs in the middle. I dose CO2 that is timed to come one and go off with the lights.

I don't mind the light fixture being very high, just wanted to get the right height so I get the estimated PAR value for medium to high light. 

The original 4" above the tank was too close - now I know.

The ideal for me is to increase the photo period so I can enjoy the fish instead of a dark tank 2/3 of the day


----------



## shane3fan

Am I reading the chart correctly? I would have medium-high light depending on time of day? If so, that is what I was going for. 

My tank is nearly 20 inches tall and the fixture is 10 inches above the top of the tank---it is a Tek 4x39 T5HO fixture and I run 2 bulbs for 8 hours with a two hour burst of all 4 bulbs.


----------



## jgb77

shane3fan said:


> Am I reading the chart correctly? I would have medium-high light depending on time of day? If so, that is what I was going for.
> 
> My tank is nearly 20 inches tall and the fixture is 10 inches above the top of the tank---it is a Tek 4x39 T5HO fixture and I run 2 bulbs for 8 hours with a two hour burst of all 4 bulbs.


Actually according to the chart on this page above, if you have about 3 inches of substrate, your light is about 27 inches from the bottom. This gives you medium light with 2 bulbs and "too high" with all four. The importance of the chart above is the measurement of the light distance to the substrate, not from the top of the tank to the light.
I have a 4 bulb Tek fixture as well and run the bulbs on a similar schedule as you, and have it 30 inches from the substrate, so it looks like you are pretty close to where you want to be. Measure the distance from your light to the substrate, you want that to be about 30-32 inches to get medium with 2 bulbs and high with all four.
Of course all this is pending Hoppy's input, as he knows a lot more than I do about this.
Hope this helps,
John


----------



## Doc7

sundragon said:


> The ideal for me is to increase the photo period so I can enjoy the fish instead of a dark tank 2/3 of the day



Why not change your photoperiod? Depending on my shift schedule for a given time of the year my tank's photoperiod is either 4-midnight or 7 pm to 3am.

Why have the lights on when you're not home?

Sent from my BlackBerry 9650 using Tapatalk


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## sundragon

Doc7 said:


> Why not change your photoperiod? Depending on my shift schedule for a given time of the year my tank's photoperiod is either 4-midnight or 7 pm to 3am.
> 
> Why have the lights on when you're not home?
> 
> Sent from my BlackBerry 9650 using Tapatalk


Haha that's what I've done. 1PM - 9PM. I work from home (across the tank) a few days a week so I'd like to push it to 11-9 or 1-11 but not at the expense of algae. The days I work from the office, I'm gone from 9-9 so I don't get to feed them those days because the lights are out.

I should make it later in the day so I can enjoy them later in the evening - just feels weird.


----------



## brooklynfishman

So Hoppy, In refference to my other post about CO2, you are saying that I should have 2 or 3 T5HO bulbs ontop of my 24 inch deep tank? (fixture is about two inches above the tank.

Right now I am using 4 for 10 hours with all 8 bulbs for a 3 hour burst.

Could this be the reason I am having trouble maintaining my CO2 levels perhaps?

This could answer why my plant growth is SOOO compact. I thought that they were just not growing that fast...


----------



## Hoppy

brooklynfishman said:


> So Hoppy, In refference to my other post about CO2, you are saying that I should have 2 or 3 T5HO bulbs ontop of my 24 inch deep tank? (fixture is about two inches above the tank.
> 
> Right now I am using 4 for 10 hours with all 8 bulbs for a 3 hour burst.
> 
> Could this be the reason I am having trouble maintaining my CO2 levels perhaps?
> 
> This could answer why my plant growth is SOOO compact. I thought that they were just not growing that fast...


As long as the bulbs are not close together, the number you need depends on the front to back depth of the tank. You could have a 36 inch front to back tank, and need 4 bulbs to get reasonably uniform PAR over the whole substrate, or a 12 inch front to back depth and need only one bulb. It will be a rare planted tank that will need 8 T5HO bulbs. (Assuming you are referring to real HO lights, and not FishNeedIt quality underpowered lights).


----------



## brooklynfishman

IT a 120gal so, 48 x 24 x 24. Its a stupid current NOVA Extreme light...So I know the quality is not that great... and the lights are basically right next to each other. VERY hard to change them since they are so close together Tom just turned me on to the ATI, but guess I will need to save up for that ...

Just wondering, if the fixture being only 4 inches above the tank is contributing to my algea woes and if I lefted the light up 6 or 8 inches, that would give me better all around coverage and help with the algea a bit.


----------



## Hoppy

You could adjust the wiring a bit, shifting the bulb connectors so you can run just the 2 outer bulbs on each side. That would probably be about the right amount of light, given the relatively poor reflectors on that light. I don't know if you can do that, but it would be worth trying.


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## jseyfert3

Okay, I found this thread from aquatic plant central.

The basics:
The only plants I've ever grown are some Java Fern in a 20 gallon long with a 2 bulb T12 fixture. No reflector, no ferts. They did fine, although growing slow, for awhile. Now that I started doing research, I found out they just have a deficiency. I'll get that fixed as I do more with planted tanks.

Now to my question. I am setting up a second 20 gallon long tank, and wish to make it a planted tank. First with DIY CO2, then pressurized CO2 in a month or two when I have the money. I, however, need a lighting system. I found this 30" 48W T5 fixture, but the guy who replied to me at APC said that was too much light, and to check your thread. Now that I've found it, I'm not quite sure. You speak of high quality reflectors, but didn't mention wattage/etc. I looked at AH Supply, and their lights look nice, especially as I do not mind building my own wood top to contain the lights. 

Would two of their 18W systems be too much for a 20 long? If so, do you have a suggestion, and if not, how high should I mount them?

This is my first planted tank so I still have lots to learn. I hope you don't mind me registering just to ask this!


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## Hoppy

A 20L tank is only 12 inches high and 12 inches front to back depth, 30 inches long. One T8 bulb will give you good low light. A Coralife 30 inch long T5NO light will give you low medium light. Anything more than that is going to be very high light. Of course you can reduce the intensity by raising the light above the top of the tank. But, why pay for so much more light than you need, then struggle to dim the light enough for it to be usable?


----------



## jseyfert3

Hoppy said:


> A 20L tank is only 12 inches high and 12 inches front to back depth, 30 inches long. One T8 bulb will give you good low light. A Coralife 30 inch long T5NO light will give you low medium light. Anything more than that is going to be very high light. Of course you can reduce the intensity by raising the light above the top of the tank. But, why pay for so much more light than you need, then struggle to dim the light enough for it to be usable?


I'm looking for medium light, so do you have any suggestion? Cheap is always good. I didn't find any single bulb T5 Coralife fixtures.


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## Hoppy

The Coralife 30 inch 2 bulb T5NO light gives you low medium light, and it is pretty cheap. You can also put screw-in CFL bulbs in an old incandescent light hood, or modify a light hood to hold at least 3 screw-in bulbs, and get just about any level of lighting you want.


----------



## jseyfert3

Thank you!


----------



## LostInFound

I made a post earlier in the general forums here but I wanted to ask a certain lighting related question here. 

Based on my cheap t5ho Odyssea 4x 24watt fixture with poor reflectors. Having all 4 bulbs on over my 36 gallon bowfront tank specs (the 36" bow is 30" long by 15" wide and 21" tall) with the light sitting at about 2 inches over the top. That should barely put me at high light range based on the graph?


----------



## Hoppy

I wish I had some PAR measurements for the Odyssea light, but I don't. So, I can only guess about what it will do.


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## fjord

*Lighting for 70 Gallon; 36 x 18 x 25*

I have a 70 gallon 36" L x 18" D x 25" H and would appreciate advice regarding fixture selection. I was originally using a Marineland Reef Capable LED fixture and was actually pleased with the results, but it failed under warranty and I was unable to get a replacement at the time, so I went with a 2 tube T5 Solarmax HO from a local dealer. Lighting seemed ok, but not for the front to back depth of the tank. It always seemed dark at the front or back depending on placement. Now I'm considering a 3 or 4 tube T5, either Catalina (3) or TEK lighting (4), but am concerned about brightness. I fear the 4 tube might scald the plants, and according to my assessment of the PAR graph, lighting would be about 160, and 120 with 3 tube, with fixture about 4" above the glass canopy. I'd prefer to keep it low tech without CO2. Could anyone make a recommendation based on configuration or brand? Thanks!


----------



## styxx

Chucklett said:


> OK. thanks for your thoughts Hoppy. Very much appreciated.
> 
> Your opinion makes sense as LEDs are a direct light source, so logic dictates that you would need almost a "net" of LEDs to cover the surface area of water.
> 
> I will continue to research my options of how to obtain the shimmer effect and lush plant growth whilst keeping everything under the hood.
> 
> Thanks again :smile:


I can't speak to the GroBeam 500s, but I use the 1000ND LED Fixtures and here's the information on them, originally found here:

TMC GroBeam 1000 Natural Daylight
PAR Data(Source) PAR Vs. Distance from source
195 PAR @ surface (7” through air)
120 PAR @ 10”
80 PAR @ 14”
52 PAR @ 19”
41 PAR @ 25”
Notes: Uses 10 x 6500K Cree XP-E Compact PowerLEDS


----------



## Craigthor

One of the salty guys stopped by with the par meter today and here is what we came up with. Numbers were really consistant from left to right and up and down on both side. Readings were taken with an Apogee Meter lights suspended about 4.5" over the top of the tank.

2 bulbs on - 1 Giesemann AquaFlora : 1 Giesemann Midday

right under water surface: 110
half way down tank: 60
right on bottom glass: 25

4 bulbs on - 1 Giesemann AquaFlora : 1 Giesemann Midday : 1 ATI Blue Special : 1 GE Starcoat 6500k

right under water surface: 175
half way down tank: 80
right on bottom glass: 50

6 bulbs on - 2 Giesemann AquaFlora : 2 Giesemann Midday : 1 ATI Blue Special : 1 GE Starcoat 6500k

right under water surface: 280
half way down tank: 100
right on bottom glass: 70

This was based on a Current Nova Extreme 12x 39 watt T5HO with 6 bulbs over each half the tank. The tank is 30" tall with the light about 4.5" over the tank top.

So with my 2 bulbs on each side turned on I have plently of par to keep low light at the very bottom with more further up if I wanted to keep something slightly more demanding.

Craig


----------



## audioaficionado

Craig, it sounds like you could also have a nice midday burst without it becoming an algae farm.


----------



## fishyjoe24

what type of reflectors would you consider the hagen glo retro fit reflectors to be. poor fair or good? using those reflectors with a t5 h.o what type of lighting would i get with it 10 inches from the top of a 10g?


----------



## ArchimedesTheDog

So from reading as much of this epic thread as I could, for an 18-inch-tall 29-gallon tank, I want a single bulb T5HO if I put it directly on top of the tank (I don't really have a lot of capacity for suspension). This will give me Medium-high light, correct? All I have seen is duals... What about smack in the middle of medium?


----------



## ArchimedesTheDog

Ah, I am dumb. With 2 inches of substrate I am looking at 16", so the calculations are all there.


----------



## 2in10

fishyjoe24 said:


> what type of reflectors would you consider the hagen glo retro fit reflectors to be. poor fair or good? using those reflectors with a t5 h.o what type of lighting would i get with it 10 inches from the top of a 10g?


The reflector is fair to good and the lighting level depends on how many bulbs you are using.


----------



## BS87

Ok, so i read (almost) all of this thread. Learned a lot (I think?). and at times I have thought I had a handle on this, and others simply confused 

I'm planning on setting up a 40B that will (eventually, as it grows in) be heavily planted, though not like a jungle. Maybe a 40B version of Plantbrain's dutch-style tank? Not sure yet.

I'd like to sit at around medium-intensity lighting, as I will not be doing CO2 right away, but I do plan on it eventually. I'll be using a max of 3" of substrate, and the 40B is roughly 16" tall. I had planned on using a Catalina 1x T5 hood, and using the legs to place it above the tank. It looks like the legs would raise it about 2-3" off the rim of the tank. Would a single bulb fixture be able to effectively light the 18" depth of the tank? I could do two of the single bulb fixtures, spaced out, but I fear this would be too much light, and I know that the Catalina fixtures have nice reflectors. At this point I've confused myself, and don't know if I need a single T5 HO, or a dual bulb. Or if I just need some T5NO (which, unless I'm blind, I can't find on Catalina's website). Or if I should just DIY some LEDs and drop $$$  )

Help!


----------



## Hoppy

BS87 said:


> Ok, so i read (almost) all of this thread. Learned a lot (I think?). and at times I have thought I had a handle on this, and others simply confused
> 
> I'm planning on setting up a 40B that will (eventually, as it grows in) be heavily planted, though not like a jungle. Maybe a 40B version of Plantbrain's dutch-style tank? Not sure yet.
> 
> I'd like to sit at around medium-intensity lighting, as I will not be doing CO2 right away, but I do plan on it eventually. I'll be using a max of 3" of substrate, and the 40B is roughly 16" tall. I had planned on using a Catalina 1x T5 hood, and using the legs to place it above the tank. It looks like the legs would raise it about 2-3" off the rim of the tank. Would a single bulb fixture be able to effectively light the 18" depth of the tank? I could do two of the single bulb fixtures, spaced out, but I fear this would be too much light, and I know that the Catalina fixtures have nice reflectors. At this point I've confused myself, and don't know if I need a single T5 HO, or a dual bulb. Or if I just need some T5NO (which, unless I'm blind, I can't find on Catalina's website). Or if I should just DIY some LEDs and drop $$$  )
> 
> Help!


Suspend the one bulb T5HO light about a foot above the top of the tank and you will get reasonably uniform light over the whole substrate, plus the PAR will be down to the low medium area, which is good.


----------



## BS87

Excellent thanks. I was a bit confused because according to this table" 









That would put me at "low" but the Catalina's have good reflectors, which I thought would bump me into "medium" range ( which agrees with the T5HO graph on page one). So the single T5HO about a foot above (so 24-25" from the substrate) should be sufficient? And when i start doing CO2, I would be able to lower the light closer as I increased my CO2 setup/knowledge etc. Now to decide, 6500k or 10000k? hmm hah. Catalina's dual bulb fixtures are nice, but I'd rather not incinerate my plants!

Thanks Hoppy!


----------



## BS87

Also, If I need to put a glass lid (acrylic made? that might melt) on the tank (cat....), how much does that reduce the light? I have seen figures anywhere from 10%-50% and there does not seem to be a hard consensus.


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## ~~~

So what you are saying is that 4 T5HO bulbs, at any length, are too much light for about 4 inches suspended over a 166 that is 24" tall?
oi
I thought that 1.3 wpg put me in low-medium light, but It's too high?
Wowa. Anddd I have no CO2.


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## TwoTacoCombo

I'm putting together a low light planted shrimp breeding tank. It's a 20G Long (36x12x12). Would I be OK with a 30" dual t5no fixture suspended 14 inches above the substrate, or is that too much and I'd be better off with a single bulb fixture just sitting on the tank 10 inches above the deck?


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## jcgd

~~~ said:


> So what you are saying is that 4 T5HO bulbs, at any length, are too much light for about 4 inches suspended over a 166 that is 24" tall?
> oi
> I thought that 1.3 wpg put me in low-medium light, but It's too high?
> Wowa. Anddd I have no CO2.


My hair dryer turned on over my tank gives me 2 watts per gallon and absolutely no light. The watts mean nothing.


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## TwoTacoCombo

Actually, it's giving off loads of light, but not in the part of the spectrum that's usable by plants or visible to the human eye. This is the basis of the 'watts are useless' argument. A watt is just a function of energy over time. How that energy is turned into light (and of which frequency) is the huge variable between lighting systems. 1.3 LED wpg is nowhere near the same as 1.3 incandescent wpg.


----------



## madness

TwoTacoCombo said:


> I'm putting together a low light planted shrimp breeding tank. It's a 20G Long (36x12x12). Would I be OK with a 30" dual t5no fixture suspended 14 inches above the substrate, or is that too much and I'd be better off with a single bulb fixture just sitting on the tank 10 inches above the deck?


Isn't a 20L 30" long?

A standard T8 with a 6,500K bulb might work for a low light shrimp only tank.

A dual T5NO would likely be too much light judging from the way that my dual T5NO (sitting on top of the tank) sort of scorches things directly underneath the fixture on my 40B.

A single bulb T5NO might be perfect but they aren't really available at a reasonable price that I know of.

I am facing the same dilemna of trying to light 20L shrimp tanks at the moment. Leaning towards LEDs to limit evap probably though I will probably use a 2 bulb T5HO fixture that I have on one of them and just counter the algae with a lot of floating plants and looking the other way (ignoring it).


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## TwoTacoCombo

You're right, a 20L is 30". My other tank is 36" long, so the fingers got confused. I found a 30" single T5no on Amazon last night. It's not much cheaper than a dual fixture, but we'll see how well it works out. I looked into the Marineland single bright setup, but there were a few comments about uneven lighting, especially on a shallow tank like the 20L.


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## Hoppy

By far the most T5NO aquarium lights now in use are Coralife lights. Here is a chart of measured PAR for that light:









From that you can see that you should get between 25 and 30 micromols of PAR at 14 inches, which is good low light.


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## TwoTacoCombo

I actually ordered the single bulb version. i'll be mounting it directly on the rim, 10 inches from the substrate. Is it safe to assume that I can halve the values on that chart, and get ~25 at 10"?


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## kubalik

I have a question , I have a tank that is 24 inches high, 18 inches wide, 41 inches long .
I have 2x dual T5HO hagen glo fixtures over it . Now how high should I install the fixtures to be in medium-high light range ? Thx .


----------



## mrxsys

*50 Gallon lighting question*

I'm looking for medium lighting for a 20" deep 50 gallon tank. From what I've been reading there seems to be a lot of mixed opinions about the odyssea t5 lights (cheap reflectors, bulbs etc) based on the graphs in this thread it seems like the AH supply kits would outperfom these cheaper made T5ho lights. 

So is it safe to say a AH supply kit should achieve better lighting then a t5h0 light with poor reflectors and ballasts?

Please be gentle I'm noob when it comes to this stuff


----------



## Hoppy

TwoTacoCombo said:


> I actually ordered the single bulb version. i'll be mounting it directly on the rim, 10 inches from the substrate. Is it safe to assume that I can halve the values on that chart, and get ~25 at 10"?


No, it isn't a safe assumption, because so much depends on how good the reflectors are. Coralife reflectors are almost worthless, but they still do add something to the amount of light you get. If you use a light with no reflector, or a light with a good reflector, you will get other than half of what that chart shows.


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## Hoppy

kubalik said:


> I have a question , I have a tank that is 24 inches high, 18 inches wide, 41 inches long .
> I have 2x dual T5HO hagen glo fixtures over it . Now how high should I install the fixtures to be in medium-high light range ? Thx .


You may get medium-high light with the lights sitting on top of the tank. Until someone makes some good PAR measurements with those lights, all I can do is make a guess, based on what they look like. If you keep the two light fixtures separated by 8+ inches, roughly, the light intensity won't be double that of one light, just more uniform over the substrate.


----------



## Hoppy

mrxsys said:


> I'm looking for medium lighting for a 20" deep 50 gallon tank. From what I've been reading there seems to be a lot of mixed opinions about the odyssea t5 lights (cheap reflectors, bulbs etc) based on the graphs in this thread it seems like the AH supply kits would outperfom these cheaper made T5ho lights.
> 
> So is it safe to say a AH supply kit should achieve better lighting then a t5h0 light with poor reflectors and ballasts?
> 
> Please be gentle I'm noob when it comes to this stuff


It is safe to say that an AH Supply kit should give you more light than a T5HO light with poor reflectors and a low power ballast. Whether that is better or not depends on how far it is from the substrate. You will use more electricity with the AH Supply light than with the T5HO light.


----------



## Rainer

Hoppy said:


> Another way to use this is to convert it into a simple table, that lets you select a lighting option based on tank height, how high you want the light to be above the top of that tank, and how much light you want. This assumes that multiple bulbs are mounted close together, reflectors are typical for that particular type of light. And, I left out the AH Supply light kits.


The information in the original post has changed and expanded considerably since I set up my high-light tank. IIRC, the first graph was produced with Catalina-style reflectors in mind and I presumed the table was as well, although I now note it is intended for reflectors typical for that style of light. Instead of high light, the 2x T5HOs mounted 4" above my 29g could be providing too much light, which may explain a few things. 

Could you please clarify?


----------



## kubalik

Hoppy said:


> You may get medium-high light with the lights sitting on top of the tank. Until someone makes some good PAR measurements with those lights, all I can do is make a guess, based on what they look like. If you keep the two light fixtures separated by 8+ inches, roughly, the light intensity won't be double that of one light, just more uniform over the substrate.


Thank you Hoppy.


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## Hoppy

Rainer said:


> The information in the original post has changed and expanded considerably since I set up my high-light tank. IIRC, the first graph was produced with Catalina-style reflectors in mind and I presumed the table was as well, although I now note it is intended for reflectors typical for that style of light. Instead of high light, the 2x T5HOs mounted 4" above my 29g could be providing too much light, which may explain a few things.
> 
> Could you please clarify?


I am always learning something else about light and what different lights can do on an aquarium. Since that table was made up I have learned a lot. For one thing I now know there is a wide range of reflectors in use with widely varying effectiveness. That led me to post some photos of typical reflectors and how I would rate them.

I also now believe that my original ranges for low, medium and high light were off. Now I would say that 20 to 30 micromols is low light. 40 to 50 is medium light. 60 and up is high light.

I haven't made much effort to keep modifying the original charts/tables. If I were to do this again I think I would make a major effort to get PAR data for most of the popular manufacturers light fixtures, and post PAR vs Distance charts for each of them. I have done that for a few already - Coralife T5NO, a couple of Catalina lights, a FishNeedIt light, CFL lights, etc. That is by far the most useful way to present this type of information. It is too bad that the manufacturers don't provide this data, as some LED light makers now do.


----------



## Rainer

Hoppy said:


> I also now believe that my original ranges for low, medium and high light were off. Now I would say that 20 to 30 micromols is low light. 40 to 50 is medium light. 60 and up is high light.


Where does the "Too High" category begin? And at what duration does it become a problem? 

My bulbs are offset by 6" (30" tank, 24“ staggered bulbs), meaning the outer 12" receive less light than the center when both are on. If I throttle back to using the bulbs sequentially to ensure full coverage at a more sensible PAR value, would a brief overlap (ie "noon burst") of 1-2 hrs be harmful?


----------



## Hoppy

Too high is subjective. I think it is where you have little chance of providing enough CO2 to meet the plants needs at the growth rate the light is driving them to. But, what PAR that is I don't know. Anything over 100 is almost certainly "too high". But, the limit may be lower. I don't agree with the value of short bursts of higher light, but I realize that I could easily be wrong.

A T5HO light can be a FishNeedIt light, and be only a little brighter than a T5NO light. Or it can be a Tek light, and be much brighter than T5NO lights. Without knowing which T5HO ligh you have on the 29 gallon tank I don't know how harmful a "noon burst" could be, if it is harmful at all.


----------



## Wannaberooted

First post, one of the members of The Rocketry Forum suggested I join here after I posted about aquariums there. I am about to start a 20 gallon low tech planted tank. Here's a picture.







The light is a Zoo Med Aquasun, T5 HO 2x24 watt. The reflector is polished aluminum, flat for about three inches in the middle, with octogon edges for a total of about 5 inches. I have one 5000k Flora Sun bulb and one 6500k Ultra Sun bulb, both 22 inches long. I'd prefer to mount it as pictured, 16" above the future Flourite substrate for low light. So the solution to get to low light could be as easy as adding two layers of fiberglass screen underneath the light's plastic guard? The bulbs have separate switches so one could be off for part of the day if need be. There is also a Aqueon glass hood underneath the light the brackets are sitting on, to reduce evaporation. Thanks very much for any help. I'm going to start cycling the tank tomorrow.


----------



## Rainer

Hoppy said:


> Too high is subjective. I think it is where you have little chance of providing enough CO2 to meet the plants needs at the growth rate the light is driving them to. But, what PAR that is I don't know. Anything over 100 is almost certainly "too high". But, the limit may be lower. I don't agree with the value of short bursts of higher light, but I realize that I could easily be wrong.
> 
> A T5HO light can be a FishNeedIt light, and be only a little brighter than a T5NO light. Or it can be a Tek light, and be much brighter than T5NO lights. Without knowing which T5HO ligh you have on the 29 gallon tank I don't know how harmful a "noon burst" could be, if it is harmful at all.


Sorry for not being clear, Hoppy; it's a Catalina with individual reflectors.

Despite expectations from the nominal PAR value, the light from using only one of the bulbs seems dim, especially with the floater cover I had until recently, so a "noon burst" would be welcome at prime viewing time if it doesn't do any damage.

Thanks for all the work you've done here to help out the community - it's been a welcome resource.


----------



## rebus20

I have a 55 gallon with a single t5ho hagen glo fixture which I think puts me into the med light range. I just bought a co2 bottle and regulator and was going to heavily plant my tank so I was considering upgrading to a dual t5ho for high light. Would buying a new cheaper end($100) fixture be better than buying another hagen 48" single and having 2 on the tank?
Someone on here told me to keep my current light until I get my co2 straightened out and my ferts down then consider a new light. Any opinions?


----------



## S&KGray

rebus20 said:


> Someone on here told me to keep my current light until I get my co2 straightened out and my ferts down then consider a new light. Any opinions?


Very good advice :thumbsup:


----------



## jcgd

A link with the definition of PAR, units of measure of light and conversion calculators. Thought somebody might find it useful. 

http://www.egc.com/useful_info_lighting.php


----------



## Bananariot

lmao I have a t5no on my 12 gallon long. Directly above the tank. one 6500k bulb. Probably 6-7 inches above the substrat. I'm scared to know the answer to if it's med or high light......


----------



## ThatGuyWithTheFish

Hoppy, do you have any PAR data on Catalina lights?


----------



## Hoppy

ThatGuyWithTheFish said:


> Hoppy, do you have any PAR data on Catalina lights?


Yes, I do:


























This last one I don't remember the specific light fixture it came from.


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## ThatGuyWithTheFish

Hm, I got the 1x24W 30" for my 20 long. How many inches do you think I should hang it? 4? 6?


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## Hoppy

ThatGuyWithTheFish said:


> Hm, I got the 1x24W 30" for my 20 long. How many inches do you think I should hang it? 4? 6?


What manufacturer? There are big differences among FishNeedIt, Catalina, Aqueon, Hagen, etc.


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## ThatGuyWithTheFish

Hoppy said:


> What manufacturer? There are big differences among FishNeedIt, Catalina, Aqueon, Hagen, etc.


Sorry, Catalina.


----------



## Hoppy

I would hang a one bulb Catalina light 21-24 inches from the substrate.


----------



## mrsdorothy

I'm setting up a 29g planted tank and ordered this light for it. Nova Extreme 2xT5HO Im going with a 2-3" of substract. How high would I have to hang this to have medium light. Can only use 1 bulb if necessary. Had planned on using the mounting legs but will hang it if necessary.

http://www.amazon.com/gp/product/B00176787O/ref=oh_details_o00_s00_i00


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## Hoppy

I don't have, nor have I seen, PAR data for the Nova Extreme T5HO lights. As I recall, those have just fair reflectors. Based on that, I think hanging the light about 8 inches above the top of the tank would give you around 50 micromols of PAR, medium light.


----------



## tylergvolk

Hoppy,

Thank you for taking the time to share your data with everyone. Being fairly new to the hobby, I found that your data was very easy to read and figure out.

I wanted to share some photos of my next setup I am currently planning in hopes of your feeback as far as my lighting is concerned.

I currently have a Biocube 14g with 2 Coralife Daylight 10,000K bulb 24 watt 13" bulbs. and room for a third. (See Pictures)

The reflector is what I could consider moderate/good, but not excellent. (See Pictures)

My blubs will be about 12 inches from the substrate once I have everything setup (See Pictures)

If I am reading your data right, then 

-I will have MEDIUM LIGHT if I run 1 Coralife Daylight 10,000K bulb 24 watt 13" bulb. 

or

-I would be at HIGH LIGHT running 2 Coralife Daylight 10,000K bulb 24 watt 13" bulbs.

Would you say that is accurate?


View attachment 50980


View attachment 50981


View attachment 50982


View attachment 50983


View attachment 50984


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## dannylc

Sorry guys but not a clue how to work this out, from looking at the pictures I have good/very good reflectors.

The lighting and tank are this,

I have a choice between 4 and 6 bulbs ( 3 units with x2 bulbs on each ), each bulb is a 54w HO T5 and 5000lm per bulb.

My tank is 48"x24"x30" ( lwh )

Can anyone tell me what par that would create and how far above the water surface they should be if I use 4 or 6 bulbs.

Thanks


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## Hoppy

Tylergvolk you should get medium to high medium light with just one of those PC bulbs. The reflector is a poor one, because it isn't shaped to reflect light from the sides of the bulbs, and most of the light reflected from the back of the bulb just strikes the bulb, doing no good. You shouldn't need any more light than from just one bulb.

Dannylc, you have two problems: the 30 inch height of the tank, and the 24 inch front to back depth. The latter will require that you use more than a single light fixture over the center of the tank. The first means that a single T5HO bulb gives you only low light.

One option would be a Catalina Aquarium custom light based on http://www.catalinaaquarium.com/store/product_info.php?cPath=71_194&products_id=1820 but with two sets of 2 bulbs separated by about 12 inches. Or you could have 3 sets of 2 bulbs, with the middle two on a separate power cord, so you could use it for a "noon burst" of high light. You would have to phone Catalina Aquarium to get a price on that. You could suspend that about 6 inches above the top of the tank to get around 40 micromols of PAR.


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## planBtypeA

ok guys, tried to read this whole post (took a while) and came up with a question im sure i missed. i have a 60g acrylic roughly 20" tall, how much will the acrylic top affect the par of the lighting. im planning running a 54w x 4 6700k t5ho setup with 2 bulbs on around 0800-1400 and the other 2 from 1100-1800 with led moons from 1700-2200. im shooting for the mid medium to lower high level. i will be running a 20g sump (tank was free and already drilled) with ferts and co2.


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## Hoppy

If you keep the acrylic top clean it shouldn't have a significant effect on PAR. But, if it stays dirty, with a white film on it, it might drop the PAR enough to have to account for it.


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## planBtypeA

thanks hoppy. looks like i have some more refinishing to do...


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## Gafi

Just wondering how much of a reduction in light a center brace on the aquarium has on the center part of the tank? Is it a significant loss? Is there any way to get around this?


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## planBtypeA

im guessing (feel free to correct if im wrong) that the loss for you will be the same as hoppy told me, minimum as long as its pretty clear and clean. if its a solid brace, ie wood/metal, depending on the width you might get a pretty good shadow from it.


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## Hoppy

One way to get an idea about how much light loss the brace gives you is to take a photo of the tank, with the lights on, and look at the variation in brightness throughout the tank. If you adjust the exposure down so nothing is overexposed you can see light differences easier than by just looking at the tank, or at least I can. If you can see the difference, the PAR reduction is not trivial. (Our eyes are very bad as PAR or even lux meters.)


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## Airena

I have a 44g 24" high corner tank with a 2x24w T5HO fixture on top of the tank. According to the chart if I run one bulb I'd have low light and if I run tow I'd have high light. Does the watts of the bulb make a difference?


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## tylergvolk

Hoppy said:


> By far the most T5NO aquarium lights now in use are Coralife lights. Here is a chart of measured PAR for that light:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> From that you can see that you should get between 25 and 30 micromols of PAR at 14 inches, which is good low light.


Appreciate the help Hoppy!


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## BobinCA

Hoppy,

I have a 48"x24"x24 aquarium.
12 yrs ago I installed an AH supply lighting system inside the canopy.
consisted of 3 rows of lights, front to back. 2 PC's in each row. Each row has its own ballast. And, of course, AH supply reflectors.
Bulbs are PC 55W, 6700K.
The ballast that controls the front row is dead, so no bulbs in that row.
I desire a low light tank, with minimal CO2 (pressurized) injection.
Type of plants are Anubias varieties, Crypts, Java Fern.

Since the front row is missing in action, what would be the best arrangement of bulbs to get the best "spread" of PAR in this tank?
Based on above specs, I run the middle row, 110W total, for 10 hrs/day.
From 12N to 3PM the back row comes on for a grand total of 22OW during that 3 hr time period.
Is this a high light tank? Med light tank? ....desire a low light tank.
Just a thought, given the 24" spread from front to back, what if I removed one bulb from each row ie: right rear row PC and left middle row PC and burned those bulbs for the entire 10 hour photoperiod? Would that give me a more even spread of light?....or....just deactivate the rear row and burn the 2 bulbs in the middle for the full 10 hours?
Your thoughts are appreciated.
TY


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## Hoppy

I would remove the inactive row and move the middle row to the front, with the two rows about a foot apart. That should give you uniform 30 micromols of PAR over most of the tank, which is low light, but about the maximum you can go as low light - non-CO2.


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## BobinCA

Hoppy, 

Very logical idea...I will do it.
What do you think of injecting, given the parameters of light, 1 bbs of CO2?
(anubias, java fern and crypts) in this 125 gal. tank? Would it still be a low light, low tech tank?


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## Hoppy

BobinCA said:


> Hoppy,
> 
> Very logical idea...I will do it.
> What do you think of injecting, given the parameters of light, 1 bbs of CO2?
> (anubias, java fern and crypts) in this 125 gal. tank? Would it still be a low light, low tech tank?


CO2 is very good for the plants no matter what level of lighting you have. For a 125 gallon tank 1 bubble per second would be a very minimal amount of CO2. My DIY system gives me about that bubble rate on my 65 gallon tank, and it makes a huge difference in how the plants grow. So, for sure 2 bbs would be helpful on a 125 gallon tank. Just remember the effectiveness depends a lot on how you diffuse the CO2 into the water. If you want to you can use a high bubble rate with low light - it does no harm and helps the plants a lot.


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## Ajax_xajA

Great write-up, awesome charts, and great explanations! No wonder people look to you as THE planted tank guru.

Hopefully you can answer a quick questions for me though, as I seem to be getting various responses and answers from different people. I've got a 12G Long Mr. Aqua, with a 2x39W t5HO current nova fixture sitting on top (lifted 4 inches) and only running one 10k bulb. According to your chart, I should be sitting in high light territory, but nothing seems to be growing properly (plants seem starved) . This was in a CO2 injected environment as well. People from my local forum are stating that this is WAY too much lighting, even if I were to lift it a few more inches, and to downgrade to an NO fixture. What's your take on this? Does wattage / color spectrum factor into any of this?


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## Hoppy

I strongly suggest going to http://www.plantedtank.net/forums/showthread.php?t=184368 for much more current information on PAR from various lights. Most of the charts, if not all of them, in this thread are not current. Since this thread began a lot more PAR meters, and lux meters have been obtained and data from a lot more lights is now available. This new data demonstrates that the less expensive T5HO lights are not nearly as bright as the expensive ones, and it includes PAR vs distance data for many of the inexpensive ones.

So far no one has posted PAR vs distance data for the Current Nova fixture, so I can only guess how much PAR it produces. But, it is highly unlikely that a 12 gallon long tank with any T5HO light, even one 4 inches above the tank, would be anything but high light. Wattage and color spectrum are not the significant factors in how much PAR you get.


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## BobinCA

*Effect of PAR with distance*

Hoppy,
I visited the post that displays your latest PAR values vs. distance for various types of lighting.
I happen to have an AH Supply PC 55W 6700K bulb. According to the chart my plants would have to be, at a minimum, 23" or more in distance from the bulb to be at 30 micromols or less. My tank is 24" in height. If I tie Anubias to driftwood, thereby raising them up in the tank, my average height for my Anubias plants is probably around 15". From the chart I can only assume that they are in the region that would be classified as "high light". And I wanted a low light tank (less than 30micromols). Am I interpreting this correctly?


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## Hoppy

BobinCA said:


> Hoppy,
> I visited the post that displays your latest PAR values vs. distance for various types of lighting.
> I happen to have an AH Supply PC 55W 6700K bulb. According to the chart my plants would have to be, at a minimum, 23" or more in distance from the bulb to be at 30 micromols or less. My tank is 24" in height. If I tie Anubias to driftwood, thereby raising them up in the tank, my average height for my Anubias plants is probably around 15". From the chart I can only assume that they are in the region that would be classified as "high light". And I wanted a low light tank (less than 30micromols). Am I interpreting this correctly?


Yes, you are interpreting it correctly. That is one reason why hanging lights a foot or more above the top of the tank works so well. That greatly reduces the difference in PAR from substrate level to top of water level.

When we say 20-30 micromols of PAR at the substrate is low light, that is considering the fact that higher in the tank the PAR is much higher. The only way you can have the same PAR throughout the tank is to have the light far, far above the tank, maybe 10 feet above the tank (?) I don't know if having 20 micromols throughout the tank would be enough to keep the plants growing well or not, since that would be a very rare occurrence.


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## britintexas

*Rocket Science?*

What is all this high-falluting PAR stuff ? All I want is to be able to put enough light into my 30 gallon 18" high aquarium so I can grow plants without breaking the bank! Jeesh, my dad did it successfully in London in the 70's without CFL's T5/8 etc!!!! SURELY it shouldn't take ALL this nonsense just to grow plants in the above aquarium in a hard water area with a Fluval 88g CO2 unit attached!

I'm a computer tech and I get fed up with other "techs" confusing my clients with unecessary "geekspeak", and sorry, but that's exactly what I am reading above!


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## [email protected]

"We" had computers in the 70s as well, but those have changed just a bit over time. One major change is we have computer techs, instead of graduate electrical engineers. 

Your dad wasn't growing some of the fantastic range of plants that people are into forty years later.


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## Steve001

britintexas said:


> What is all this high-falluting PAR stuff ? All I want is to be able to put enough light into my 30 gallon 18" high aquarium so I can grow plants without breaking the bank! Jeesh, my dad did it successfully in London in the 70's without CFL's T5/8 etc!!!! SURELY it shouldn't take ALL this nonsense just to grow plants in the above aquarium in a hard water area with a Fluval 88g CO2 unit attached!
> 
> I'm a computer tech and I get fed up with other "techs" confusing my clients with unecessary "geekspeak", and sorry, but that's exactly what I am reading above!


We used to light our homes with gaslight. Times change. Technology changes. We gain knowledge.

Did you know co2 was used as early as the early 60S ?
Look see here. http://web.archive.org/web/20060504235513/http://www.cryptocoryne.com/co2_text.htm


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## Jeff5614

britintexas said:


> What is all this high-falluting PAR stuff ? All I want is to be able to put enough light into my 30 gallon 18" high aquarium so I can grow plants without breaking the bank! Jeesh, my dad did it successfully in London in the 70's without CFL's T5/8 etc!!!! SURELY it shouldn't take ALL this nonsense just to grow plants in the above aquarium in a hard water area with a Fluval 88g CO2 unit attached!
> 
> I'm a computer tech and I get fed up with other "techs" confusing my clients with unecessary "geekspeak", and sorry, but that's exactly what I am reading above!


If that's the case, any old light that looks bright enough should suffice.


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## cradleoffilthfan

what kind of lighting did your dad use?


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## Hoppy

Your dad very likely had a low light tank, which allowed him a lot of leeway on lighting with the very limited choices avaialable then. The reason for getting high-falluting is that there are so many very, very bright lights available for aquariums now, and if you just use the brightest one you can get you end up becoming an algae farmer or an algae fighter, not a planted tank enthusiast. That is what ruined many people's planted tank experience.


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## akl1212

hey Hoppy i'm new to this hobby. i'm planning to get a Catalina T5HO 24 in with 2x24 watts or Aquatic Life T5HO 24 in 4x24 watts light. which light would you recommend for a medium high/high tech tank? i am using the ADA 60p tank. Should i hang it or use the legs and if hanging how far should i do it? Or maybe there is a T5HO light you can recommend me.


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## Aquaticz

Not Hoppy but....
I have a 40 gal breeder & had catalina make a single 36 " fixture 

Best if about a foot above the water. I have it on top of the tank because I can't stand being in a football stadium right in my own living room...lol
So when the plants reach mid way on the tank, they race to the top. I do a simple trim every 2 weeks. When I say simple I mean as compared to a mid-high light tank 
HTH

As Always Thank You Hoppy for All you have done for the "aquatic lighting" community


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## Aquaticz

HI 

while doing some maintenance i realized one bank of lightswas out. I check bulbs and they are good so I figure I need A new ballast. Hmmmmmmm I said to myself , by the time I order the ballast & install it could easily be 2 weeks. I have two identical fixtures& these bulbs are expensive ( 15 - 20 each)
So I am thinking about the Finnex ray 48 inch for one tank ( one is a 75 and the other a 55 gal) and keeping one existing fixture. <br />
Anyone using the Finnex Ray for a tank that measures either 21 inches or 15 inches to the substrate. On there site there is a chart that indicates it puts out 7k . I am looking for advice ... Can U help?
Thanks for your help


Sent from my iPad using Tapatalk HD


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## KFryman

Would the Zoo Med Aquasun be classified as crappy reflectors or fair? Also what would be the optimum height for medium-high light in a standard 15g? 

What are the best bulb combos? I have a 6500k and a 5500k, but I have heard of other mixes and I feel that mine isn't the best mix, though it may be.


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## AirstoND

KFryman said:


> Would the Zoo Med Aquasun be classified as crappy reflectors or fair? Also what would be the optimum height for medium-high light in a standard 15g?
> 
> What are the best bulb combos? I have a 6500k and a 5500k, but I have heard of other mixes and I feel that mine isn't the best mix, though it may be.


The best combo provides a full spectrum, high intensity spectra in reddish and bluish wavelengths. I have good success with CFL 6500K bulbs on my 15g. Optimum height would depend on plant selection and setup. I use a Zoomed with a FloraSun and Ocean Sun on my 10g that is ~12in above water


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## Bryanmc1988

need an answer fast... do you think 1 t5 40 watts is more then enough to grow dwarf baby tears in a 40 gallon breeder tank with decor and rocks etc, it comes out to about 30 gallons of water only... let me know i am looking to redo my lights right now... 2 bulb or 1 for this tank


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## colin

I can't help but to post... this was one of the msot useful things I have ever seen posted on any aquarium forumn, thanks so much for doing the work! I way over lit my last tank, and surprise surprise, algae! I almost got a 6 bulb T5HO fixture for my 75 gal tank. Overkill!


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## Hoppy

This thread is obsolete! See http://www.plantedtank.net/forums/showthread.php?t=184368 for more up to date information, which will before long be obsolete too.


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## Allentan97

ummm..... soo i have like 600 par? what??? thats A LOTTTTTT of light.... lol 2 t5ho coralife fixture, 10 inches away at most. 6 at the closest.... hahaha 600 par


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## MarkM

*T5NO Single Bulb Data Point*

I have a 50 gal 18" high tank with 2" of substrate. My T5NO bulb is 2.5" from the water level. Par value is 42 +/-3 depending on where on the substrate the measurement is taken.


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## Allentan97

nvm... lol i just realized that this thread is old.. no 600 par for me, lol


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## zanguli

Hi members,
how are you ?

First thanks to Hoppy to bring out this chart that is very useful. I have discover this forum by this thread, an expert member of an other forum linked me this thread that is very very interesting. so every one thanks for you input in this topic.
after reading the 52 pages (that was very long but food for brain) I am a bit confuse now haha.
Let me explain.
Tank : 90x45x50 cm 
Light : NA SunFluor 4x36W osram PC hanging at 20" from the substrate
reflector is a very high polished aluminum.
the tanks is only 3 weeks old so I turn on only two bulbs.
Pressurize C02

After reading all the topic I have discover that PC gives a lower PAR reading than T5HO.

My concern is that maybe with only two PC bulb of 36 W at that height I will be too low in PAR (Tom Barr said in this topic that the limit range for most of the plant (not low light plant) will be 25-30).
So I am just afraid that maybe with this configuration I might be too short ? 

If I follow the graph with one PC bulb at 20" I will have a PAR +/- 20 so for two I will have PAR 40, Is that right ?
In fact I would like to grow a HC carpet (I have fail many time with it) I truly know that HC is a CO2 lovers and need good distribution down to the carpet to achieve a good carpet, but with that amount of light am I in the good zone to grow it, am I not too short on light? 
Would you advice me to stay in this configuration until the tank is mature and plant have made the transition, or I should turn the third bulb for the HC. I don't want to push the too high for now to be sure that HC will do the transition and not melt due the higher demand of CO2 that stronger light will thrive.

Sorry if my post is a bit confuse but it reflect my state of mind hahaha.
I wanted also to apologies if I have mad grammatical and other language mistakes, but english os not my language.

thank you very much for you help.
Regads
Zanguli


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## Mizuhuman

zanguli, this thread is considered obsolete by its creator, Hoppy
You should read the more up-to-date thread below 
http://www.plantedtank.net/forums/showthread.php?t=184368
I hope this can answer your questions


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## audioaficionado

Perhaps Hoppy can ask a mod to lock this thread.


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## zanguli

Mizuhuman said:


> zanguli, this thread is considered obsolete by its creator, Hoppy
> You should read the more up-to-date thread below
> http://www.plantedtank.net/forums/showthread.php?t=184368
> I hope this can answer your questions


Hi Mizu

Thank you very much I will post in this link. 
have a good day 

Zanguli


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## Raymond S.

I have a T5HO two bulb fixture on a ten G tank. It is borderline too high. Didn't read all the comments to see but would
like to make an observation that in other post where questions are asked from a viewpoint of "I have T5's and don't see the growth
that I think should come from their use so can someone help me/w this ?" In some of those Threads it is mentioned that
ANY glass cuts down on how much light you have reaching the plants and especially if there is any dust/calcium deposits/water
stains on it. Perhaps this is the reason that I don't see any serious amount of excess light in my tank/w the two T5HO bulbs
in there. I do use Excel as directed by the label so if I stopped using it as I plant to, I'd likely be over run by algae.
Probably only fair to mention that there is hair algae in my tank as well as green spot on the rocks which I placed on the walls
for it to cling to. The algae is not "taking over" but cultivated as part of a "natural" environment type tank with a direction in
mind as to a specific end result later after a sufficient amount of plant growth is obtained. i.e. Cut off the Excel and increase the 
percent of the Giant Duckweed growing on the top to control the light/growth level.


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## 801boom

Great read


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## Hoppy

This is an obsolete thread. I suggest reading and using http://www.plantedtank.net/forums/showthread.php?t=184368 for much more accurate and up to date information. (That thread will also be obsolete as more information is available, as more people post their light measurements for various light fixtures, and as we all learn more about the subject.)


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## lauraleellbp

Want it locked, Hoppy?


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## Hoppy

lauraleellbp said:


> Want it locked, Hoppy?


Yes, please!!!!


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