# Do I have the right understanding of Lighting Wattage?



## doncityz (May 17, 2011)

I read that the general guide is about 2wpg for 10gal. thus, I should get 20 Watts total lighting.

I now have 2 x 11w (CFL screw in type) bulbs. which is about 22W total.

But the question is, since the bulb is CFL energy saver, it says on the box 11W = 40W, so basically my lighting is 80W!? Pretty confused now. Am I having too much lighting now???? :confused1:


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## cggorman (May 9, 2009)

Read the sticky threads at the top of the forum. One addresses your specific question.


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## ReluctantHippy (Jun 23, 2011)

The bulb is 11w. The 40w is the equivalency in lumen output compared to an old school incandescent but you can't grow plants with incandescent so it really has no relevancy. 11w of CFL is equivalent to 11w of T5HO. 

I'm new to all of this but I would assume that 22w of fluorescent would be plenty for a 10 gallon tank.


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## Jadelin (Sep 30, 2009)

I think there are a couple bits of confusion here.

First off, recommended lighting level isn't specific to tank size; 2 wpg is solid low light for any size tank. So 22 watts CFL will get you 2.2 wpg gallon in your 10 and will be low medium light. You will be able to grow many plants in that amount of light. I use two 9 watt CFL in my 10 gallon and I can grow all of the standard low-light plants no problem.
The watts-per-gallon rule (wpg) only works for T8 and CFL, and even then the depth of the tank, whether you have reflectors or not, etc, etc will affect how much light actually makes it to your plants. I'm telling you this because you'll often hear people say the wpg rule is no longer valid, but for the way you're using it, it works just fine. If you want medium light get bigger bulbs that will give you between 2 and 3 watts per gallon, and if you want high light you need more than 3 watts per gallon. Personally, I'd stick with the lower light because you can still grow beautiful plants, and it's so much less work to maintain.

Secondly, 11w CFL is equivalent to 11w T8 light, not T5HO. This is important, as if you had 2 watts per gallon T5HO you would have very high light, not low light. T5NO (normal output) is about three times as strong as T8 and CFL, and T5HO (high output) is about twice as strong as T5NO, in widely rounded terms.

It's correct that it's the actually wattages and not the equivalent to incandescent wattages that makes the difference. You want 20 watts of CFL. 
An 11 watt CFL bulb puts out as much visible light as a 40 watt incandescent; it says that on the package so that people who are used to buying incandescents can buy the bulb with the right visible brightness, but it has nothing to do with how you're using it in your aquarium.


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## Steve001 (Feb 26, 2011)

Let's add some more confusion. Watts are irrelevant. Watts is a measure of electrical energy that is used during one hour of use. It's also a measure of *radiant flux*. Watts can't tell you where the output across the spectrum will be. What is relevant is
*PAR* [photosynthetically active radiation ] output,
*lumen / Lux* this determines the apparent brightness of the light and a measure of how much light falls upon one square meter of surface.
*Color rendering Index* [CRI] How accurately a light source renders colors. The closer it is to 100 the more true to life colors will be. CRI can be a little tricky. Remember sunlight is the standard it always equals 100. There are some fluorescent bulbs that have CRI's of 98+. But they only reach that high level because they simulate sunlight at times other than midday sun. Avoid those for general plant growth. Look for lights that simulate noontime sunlight and or have good PAR output. Examples http://www.aquacon.com/images/GiesemannT5Midday.html
ColorMaster Digital Imaging Lamp http://www.lightbulbemporium.com/eiko_05622ek_sp50_955k.asp

Light with high CRI will necessarily have high PAR. Lumen / lux output in flourescent bulbs is determined by the total radiating surface. Bigger bulbs equal high lumen / lux.


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## ReluctantHippy (Jun 23, 2011)

Jadelin said:


> I think there are a couple bits of confusion here.
> 
> First off, recommended lighting level isn't specific to tank size; 2 wpg is solid low light for any size tank. So 22 watts CFL will get you 2.2 wpg gallon in your 10 and will be low medium light. You will be able to grow many plants in that amount of light. I use two 9 watt CFL in my 10 gallon and I can grow all of the standard low-light plants no problem.
> The watts-per-gallon rule (wpg) only works for T8 and CFL, and even then the depth of the tank, whether you have reflectors or not, etc, etc will affect how much light actually makes it to your plants. I'm telling you this because you'll often hear people say the wpg rule is no longer valid, but for the way you're using it, it works just fine. If you want medium light get bigger bulbs that will give you between 2 and 3 watts per gallon, and if you want high light you need more than 3 watts per gallon. Personally, I'd stick with the lower light because you can still grow beautiful plants, and it's so much less work to maintain.
> ...



Yup

It's all about induction lamps. Why does no one use induction lamps? 

I would argue CFLs being closer to T5s than T8s. More similar on the lumen/w, heat output, light over surface area... I grow indoor terrestrial plants and my CFLs outperform my T5HO grow lights over and over again. Better penetration, near equal lumen, and a hell of a lot cheaper.

Both CFLs and T5HOs peak around 70 lumen/w max and operate near 55 - they vary on what wattage is ideal with CFLs being ~40w while T5HOs don't fluctuate as much. T8s are higher lumen/w but so bulky that lumen/sq in. they are much lower - CFLs are more compact than T5s so lumen/sq in they are the highest of the three. CFLs put off the most heat as they have the thickest glass and a built in ballast, T5HO's have the second thickest glass and put off the second highest amount of heat and T8s the thinnest. CFLs have the smallest surface area/lumen, then T5HOs, then T8s thus CFLs penetrate the best, then T5HO, then T8s.


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## Hoppy (Dec 24, 2005)

ReluctantHippy said:


> Yup
> 
> It's all about induction lamps. Why does no one use induction lamps?
> 
> ...


I just have to say that I disagree with most of this, as well as most of what the comment you responded to said.:hihi:


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## ReluctantHippy (Jun 23, 2011)

Hoppy said:


> I just have to say that I disagree with most of this, as well as most of what the comment you responded to said.:hihi:


I'm curious. How so? 


Here are a few comparisons. 

40w CFLs 6500k ranging from 65-75 lumen/w putting out 2,650-3,000 lumen per bulb over a 2"x2" circle with an expanding circular downward cast pattern. http://www.1000bulbs.com/category/40-watt-cfl-compact-fluorescents/

39w T5HO 6500k at 3,330 initial lumen (85 lumen/watt) over a 3' imprint with a cylindrical 360 degree cast pattern. http://www.1000bulbs.com/product/2378/FHO-39T5865ECOG.html

36w T8 at 3,335 initial lumen (93 lumen/watt) over a 4' imprint with a cylindrical 360 degree cast pattern. http://www.1000bulbs.com/category/f36t8-fluorescent-tubes/

This dated chart shows how much flouros vary based on wattage and of course you need to take into account CRI and spectrum. 











I wouldn't say a 9w CFL is equivalent to 9w of T5HO but 40w of both is pretty close. Above 40w T5 wins but above that T8 is more efficient in numbers and MH more so than that.


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## NatCh (Feb 23, 2011)

doncityz said:


> Do I have the right understanding of Lighting Wattage?)


If the answer wasn't "no" before, I bet it is now! 


I suggest you forget wpg. _Whatever_ it actually referred to, it's out of date and was (at best) inexact to begin with.


There are a couple of sticky threads at the top of this lighting sub-forum on PAR values based on light types, wattages and tank depths, which include graphs that actually make sense, that will help you determine, in practical terms, where you are and what you need to do to get where you want to be on lighting.

Hope that helps.


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## Hoppy (Dec 24, 2005)

ReluctantHippy said:


> I'm curious. How so?





ReluctantHippy said:


> Yup
> 
> 
> I would argue CFLs being closer to T5s than T8s. More similar on the lumen/w, heat output, light over surface area... I grow indoor terrestrial plants and my CFLs outperform my T5HO grow lights over and over again. Better penetration, near equal lumen, and a hell of a lot cheaper.
> ...


The thickness of the glass in the bulbs isn't relevant. Glass absorbs very little light. T5HO bulbs produce much more lumens per watt than T8's. Lumens per square inch of bulb surface is irrelevant. The heat from bulbs depends only on the efficiency of the bulb in producing light - what power doesn't produce light produces heat. There is no such thing as "penetrating" where light is concerned - all light penetrates everything equally, other than that some wavelengths may be absorbed more than others in some media, but for air or water, absorption of light is irrelevant for the lengths of optical paths we deal with. And, not mentioned, but of critical importance is the role reflectors play. A good reflector can almost triple the light output of a bulb, and T5HO lights almost always have far better reflectors than any of the other fluorescent lights.


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## ReluctantHippy (Jun 23, 2011)

Hoppy said:


> The thickness of the glass in the bulbs isn't relevant. Glass absorbs very little light. T5HO bulbs produce much more lumens per watt than T8's. Lumens per square inch of bulb surface is irrelevant. The heat from bulbs depends only on the efficiency of the bulb in producing light - what power doesn't produce light produces heat. There is no such thing as "penetrating" where light is concerned - all light penetrates everything equally, other than that some wavelengths may be absorbed more than others in some media, but for air or water, absorption of light is irrelevant for the lengths of optical paths we deal with. And, not mentioned, but of critical importance is the role reflectors play. A good reflector can almost triple the light output of a bulb, and T5HO lights almost always have far better reflectors than any of the other fluorescent lights.



Throw distance is relative and a function of the amount of lumen produced from a single point. If you had 100,000 lumen from a single MH or HPS bulb compared to 100,000 lumen from many T5s the MH or HPS would register much higher lumen levels further from the bulb than the T5's at the same distance.

Glass thickness has to do with banking heat - glass absorbs quite a bit of heat and thus the thickness has an effect on heat displacement - generally the hotter a bulb runs the less efficient it is lumen/w. 

Generally T8s produce more lumen/w than T5's once you get above 24" fixtures - you can look this up on most bulb sites. T5's are used because they are more compact - a 36w T8 is 4' whereas a 39w T5HO is 3' which is where lumen/surface area comes into play. You can fit more watts of T5HO into a given area than T8s.

Here's a blurb from another site - Here T5 lumen is about the same as T8 and T5HO is slightly less lumen/w but double the w/area. 

"T5HO VS T8 Lighting Fixture? Because this questions is asked so much I will try and explain it as best as I can. I will explain size of lamp (Bulb), wattage of each lamp, lumen output, energy savings and equivalent lighting fixture “i.e. how many lamps are equal to same output.

First, size of lamp T5′s range in size as well as do T8′s, but for this article I will be discussing T5HO’s and T8′s for 4 foot fluorescent fixtures. T5 or T5ho’s are measure in metrics and are slightly shorts then 4 feet or about 46 inches long. When buying a T5 fixture usually the fixture will measure 4 feet and the difference in size of the lamp will be made up by a extended sockets. On T 8 lamps the lamp measures from end of the pins 48 inches altogether and will fit a 4 foot fixture perfectly. The diameter of the lamps very T5 are 5 tenths of any hence the 5 in t5 and t8s are 8t tenth of an inch.

Next wattage, again several T5s out there varying in sizes which also vary the wattages for the lamps. T5 4 foot lamps vary from 28 watt non high output to 54 watt High output and the new 49 watt t5 or T5HO lamp. T8 lamps also vary wattages from length. Lamps for a 4 foot light fixture range from 24, 26 watt reduced energy bulb to 32 watt standard output which lumen output is controlled by the ballast.

This brings us to lumen output

T5 28 watt lamp equals about 2800 Lumens per lamp position

T5ho 54 watt lamp equals about 5000 Lumens per lamp position

T8 32 watt with a low power factor ballast equals about 2100 to 2300 lumens per lamp position

T8 32 watt with a normal ballast factor ballast equals about 2500 to 2700 lumens per lamp position

T8 32 watt with a high ballast factor ballast equals about 2800 to 3000 lumens per lamp position

To answer the energy savings question from the research that I have see, head to head, lumen to lumen equality vs. watts output the t8 fixture for the same amount of lumen is more efficient by about 3 percent .

So with this all said here is your fixture break down:

4 lamp 54 watt T5HO fixture equals 20,000 lumen output one to one swap with a 6 Lamp high ballast factor T8 32 which equals 18000 lumens watt fixture this is comparing a high bay fixture. 6 lamps T5ho fixture approximately equals the output of a 400 watt metal halide when new before the 3 year diminish.

Please Let me know if this help clarify this!

James Abraham"

- http://industrial-light-fixtures.com/2011/03/24/t5ho-vs-t8-lighting-fixture/


You'll notice that the T5HO puts out nearly twice the lumen of the T5 but at twice the wattage. Due to the increased heat the T5HO produces less lumen/watt - it is less efficient but still brighter due to compactness, very similar to a CFL.

Reflectors definitely make a difference though and T5's slim profile makes them easier to deal with when it comes to reflectors.


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## kevmo911 (Sep 24, 2010)

Wow. Okay, lots and lots of information and advice here, most of which is either incorrect or irrelevant. I agree with the first response: Read the PAR sticky at the top of the lighting forum.

In regards to CFL's, the 2nd sticky in the lighting forum, specifically post #21, I believe, should answer some more questions.

And, finally, in regards to Watts Per Gallon, consider this. I'll assume you agree that the higher a light is, the less "bright" it is at a certain point under the light. A 23w CFL suspended directly over a 12" high tank is maybe 2.3wpg. If you raise that light up 10 feet off the tank (ridiculous, I know, but I'm making a point), it's *still* 2.3wpg. Which tank do you think will have any growth? WPG doesn't take into effect type of bulb, distance above the tank, reflector type, or even height of the tank, all of which have significant impacts on lighting levels.

Forget watts per gallon. Just read the stickys.


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## Sharkfood (May 2, 2010)

I've never understood how a MH light can be more efficient than a flourescent considering you could use them to fry bacon. 

The only thing I can think of is the way they are measured. They are more like spotlights, whereas flourescents cover a greater area, meaning the MH reads higher PAR directly under the bulb. I know from experience you don't want a plant (terrestial) any closer than about 2' from a 250W MH fixture, whereas 2" from a 216W T5HO fixture (a 54W bulb) will not cause any damage.

This leads me to believe that much of the "efficiency" gain of a MH light is unuseable due to the difference in distance. I stopped using MH long ago, mostly because I live in an apartment nowadays and am afraid of fire, but I can't imagine why anyone would need greater light than what a T5HO can produce. Maybe someday when LEDs are cheaper/more powerful, I will change my mind.


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## Hoppy (Dec 24, 2005)

Sharkfood said:


> .......but I can't imagine why anyone would need greater light than what a T5HO can produce. Maybe someday when LEDs are cheaper/more powerful, I will change my mind.


LEDs are already pretty cheap and unbelievably powerful. One of the advantages LEDs have is that you can make a LED light that will give whatever PAR you want at whatever distance you want it to be, within limits. As little as a year ago I would have said it is almost impossible to make a LED light that can be used on a tank 36 inches high, with the light another foot and more above that tank. Today I have one almost ready to send out to the guy I'm making it for, that does just that.

T5HO lights are extremely good, but they are adjustable only by raising and lowering them. And, if they are closer than about 24 inches from where you want to achieve a PAR of 40 mms, you have to use window screen to drop the intensity. If you can't quite get the PAR you want with one bulb, the next increment is 2 bulbs, double the light. No real adjustability at all. The aquarium lights for the future are going to all be LED lights.


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## Sharkfood (May 2, 2010)

I'll have to look into LEDs some more then. (Probably has been a year since I looked into them)

The general consensus with hydroponic growers (at that time at least) has been that LEDs don't have the "punch" to grow plants. Granted, these are vegetables, etc. that need much more light than an aquairum. 

I like the idea of lowering my electric bill, which LEDs would do. 

The next project I have in the works is a Paludarium with lighting 5' above the substrate in the water portion. Would LED still be useable at that distance? I would have a 36"x28" area which LEDs could be spread across the top, but would like some area for a vent fan at least.

Apologies for the thread Hijack.


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## cggorman (May 9, 2009)

...yeah...that 3000 lumen T5 that's 4 feet long and requires a reflector to put more than 50% of its light on target? You can get the same light on target from a spot the size of your fingernail now. B)


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## Hoppy (Dec 24, 2005)

Sharkfood said:


> I'll have to look into LEDs some more then. (Probably has been a year since I looked into them)
> 
> The general consensus with hydroponic growers (at that time at least) has been that LEDs don't have the "punch" to grow plants. Granted, these are vegetables, etc. that need much more light than an aquairum.


 Nonsense, they don't nee "punch", they have Sangria.


> I like the idea of lowering my electric bill, which LEDs would do.
> 
> The next project I have in the works is a Paludarium with lighting 5' above the substrate in the water portion. Would LED still be useable at that distance? I would have a 36"x28" area which LEDs could be spread across the top, but would like some area for a vent fan at least.
> 
> Apologies for the thread Hijack.


Yes, that can be done fairly easily, using Cree XM-L LEDs with optics. That LED can be driven at 3 amps, but at half of that you could get the light you need.


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## doncityz (May 17, 2011)

Alright. Thanks for all of your inputs guys. So safe to say, my 22W total CFL is some kind of medium low lighting. Which explains why my HC is melting.


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## kevmo911 (Sep 24, 2010)

Well, maybe. More likely it's melting because you don't have injected CO2 (at least, I assume so because you didn't mention it), and HC needs CO2 to thrive. And two sideways 11w CFL's with (probably) poor or nonexistent reflectors is likely low light.


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## doncityz (May 17, 2011)

kevmo911 said:


> Well, maybe. More likely it's melting because you don't have injected CO2 (at least, I assume so because you didn't mention it), and HC needs CO2 to thrive. And two sideways 11w CFL's with (probably) poor or nonexistent reflectors is likely low light.


I have DIY CO2 injection. The rate is about 0.33 bps only. 
The lights do have a reflector. But yeah they are sideways. I agree 2x11W is still rather a low-med light. All in all, I myself is not ready to have a high light setup. im scared of them algae. :hihi:


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## ReluctantHippy (Jun 23, 2011)

Sharkfood said:


> I'll have to look into LEDs some more then. (Probably has been a year since I looked into them)
> 
> The general consensus with hydroponic growers (at that time at least) has been that LEDs don't have the "punch" to grow plants. Granted, these are vegetables, etc. that need much more light than an aquairum.
> 
> ...


The future will be LED or sulfur vapor but hydroponically speaking LEDs still are not there. They are used at some points successfully from close close distances for just the vegetative cycle but they do not pack enough punch for flowering and fruiting. Even with narrow optics I have a hard time thinking that LEDs would work 5' from substrate. **I'm new to lower light plants so I could be very wrong - I just saw hoppy's post - listen to him

They make amazing vented hoods now a days for MHs - you can now run a 1kW light just inches from the plants. 5' is pretty far and although the heat is a pain to deal with (sealed hood with fan and ducting required quite often) MH will still probably be your best bet. If you're clever you can use the ducting to warm your water though and cut down on power usage there.  - again just saw hoppy's post listen to him

It all really depends on the amount of growth you want - I'm sure you could make anything work. Can I get a link to the build if you have one? 5' paludarium sounds great.


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## Hoppy (Dec 24, 2005)

One thing I learned from ripariums is that what we consider high light is not enough to make flowering plants flower, with some exceptions. (Even African Violets, a shade loving plant, will not flower in a riparium, even though it grows well.) It comes back to the fact that sunlight is an order of magnitude more intense than we ever use over our tanks. And, flowering/fruiting plants evolved to use sunlight. But, for aquarium use, some LEDs are very capable of providing adequate light from 5 feet away.


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## cggorman (May 9, 2009)

Fruiting and flowering rely on the deep reds, which white LEDs lack. Check into the LedEngin LZ1-00R305. 660nm available up to 90w.


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## ReluctantHippy (Jun 23, 2011)

cggorman said:


> Fruiting and flowering rely on the deep reds, which white LEDs lack. Check into the LedEngin LZ1-00R305. 660nm available up to 90w.


They have specific flowering LED units for hydroponic uses that run a combination of 660nm, 670nm, 640nm reds, white, and orange LEDs. 

These will promote flowering but if you use them you end up with a red/pink paludarium. 

Both the problem and strong point of LEDs is the exact spectrum they emit. MH and HPS emit light over a broad range of spectrum much of which is wasted but a bit of which is utilized by the caratenoids and secondary chlorophylls needed for flowering and fruiting. LEDs emit almost all of their light at a specific nm (spectrum) which means you can focus on particular PAR wavelengths which most chlorophyll (chlorophyll A and B) are reactive too - this makes them very efficient at focusing on a particular stage of growth. 

From what I have read about aquarium lighting they focus on the vegetative spectrum which also happens to penetrate deeper into water with all LEDs in the unit being the same spectrum - like Hoppy said not ideal for flowering. You could always supplement your spectrum with a couple 2700k CFL spotlights if not willing to go with MH/HPS


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## Steve001 (Feb 26, 2011)

ReluctantHippy said:


> The future will be LED or sulfur vapor but hydroponically speaking LEDs still are not there. They are used at some points successfully from close close distances for just the vegetative cycle but they do not pack enough punch for flowering and fruiting. Even with narrow optics I have a hard time thinking that LEDs would work 5' from substrate. **I'm new to lower light plants so I could be very wrong - I just saw hoppy's post - listen to him
> It all really depends on the amount of growth you want - I'm sure you could make anything work. Can I get a link to the build if you have one? 5' paludarium sounds great.


Flourescent induction lighting would be an option also. It's in the beginning stages of planted tank use now.


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## ReluctantHippy (Jun 23, 2011)

Steve001 said:


> Flourescent induction lighting would be an option also. It's in the beginning stages of planted tank use now.


So pretty but so expensive. I love induction lights but that is one crazy price tag for just a super efficient fluorescent.


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## Steve001 (Feb 26, 2011)

ReluctantHippy said:


> So pretty but so expensive. I love induction lights but that is one crazy price tag for just a super efficient fluorescent.


Price depends of where you've looked. Bulbs that fit into standard household sockets are available. 
http://www.gladiatorlighting.com/products/50W-SELF-BALLASTED-U-SHAPED-INDUCTION-BULB-MEDIUM.html
http://stores.bestingreensolutions.com/-strse-Induction-Lighting--dsh--Grow-Lights/Categories.bok

P.S. Color temps run as high as 6500K


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