# how much par to shoot for



## orchidman (Dec 15, 2010)

so i was reading a thread, where someone had compiled a list of lgihts with par readings from members on TPT. very awesome nfo. but im not sure how to use this info. how much par is low light? how much is medium light? how much is high light? and about what par would co2 be a neccsity


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## IWANNAGOFAST (Jan 14, 2008)

http://www.plantedtank.net/forums/lighting/105774-par-vs-distance-t5-t12-pc.html

Looks like 40-50umols at the substrate is when CO2 is going to be necessary.


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## Dave-H (Jul 29, 2010)

There is a bit of debate about what is low/med/high light, and hoppy's chart has a lot of moving parts so it's hard to interpret it as 'absolute' ranges.

In my experience, I found that with about 28-32 mms of PAR on the substrate I am able to grow lots of things as long as I have good circulation and CO2. I had HC going (it failed, but not because of light) and now I have Ec. Belem hairgrass growing nicely, lots of blyxa and more at around 30mms of PAR.

Those plants didn't grow under my previous light which put around 14mms of PAR on the substrate. So, for me I consider anything from around 28 to 40 to be medium light. Very tricky to be exact about this, though.


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## Rockhoe14er (Jan 19, 2011)

right now i'm experimenting with around 100 par at my substrate to see if i can get some of my plants to get a bit more red. Since i have a dimmer on my LED's i set it up to where the amps tell me how much par i have at the substrate. For example 1 amp and i have 100 par at the substrate and .400 amps and i have 40 par at the substrate. I used Dave's par meter to figure this out. 

I've heard from a lot of people to shoot for 40 par but i'm board and have nothing to do for the next month.


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## orchidman (Dec 15, 2010)

i want to grow blyxa and staurogyne repens, mainly. with DIY co2... not pressurized. so would say 25 par be good?


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## orchidman (Dec 15, 2010)

here is the compilation i was talking about...
http://www.plantedtank.net/forums/diy/141245-gather-par-data-build-community-database.html


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## Steve001 (Feb 26, 2011)

orchidman said:


> so i was reading a thread, where someone had compiled a list of lgihts with par readings from members on TPT. very awesome nfo. but im not sure how to use this info. how much par is low light? how much is medium light? how much is high light? and about what par would co2 be a neccsity


This will help a lot. Remember aquatic plants are generally considered shade plants.
http://onlinelibrary.wiley.com/doi/10.1046/j.1365-3040.2000.00563.x/abstract


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## BlueJack (Apr 15, 2011)

orchidman said:


> i want to grow blyxa and staurogyne repens, mainly.


Simple and Beautiful plants


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## BlueJack (Apr 15, 2011)

I've used this chart as a general guideline










Those values may be a bit high. I remember reading somewhere that 200 umols is basically the limit for aquatic plants. Above 200 umols only marginally increases photosynthesis.

I think Dave-H is spot on when he says "28-32 mms of PAR on the substrate I am able to grow lots of things "

Also, I think par decreases by 1/2 at 12 iches and by 1/4 at 24 inches. That 30 umols at substrate in a 24 inch tank is 120 umols at the surface.


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## orchidman (Dec 15, 2010)

thanks alot!!!


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## Steve001 (Feb 26, 2011)

BlueJack said:


> I've used this chart as a general guideline
> 
> 
> 
> ...



see my link in post 7 for more practical values


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## jcgd (Feb 18, 2004)

I believe it was Tom Barr on multiple occasions stating that 40umoles on the substrate should be sufficient to grow most any plants with co2 and proper conditions.

Now this is from memory and it may have been 50umoles or something but the number is close.

Maybe Tom will correct me if this is wrong.


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## orchidman (Dec 15, 2010)

so maybe shoot for 30? how much if i dont want to use co2? 25?


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## BlueJack (Apr 15, 2011)

orchidman said:


> so maybe shoot for 30? how much if i dont want to use co2? 25?


There's a thread that I was just reading that might have the answer for you. 

http://www.plantedtank.net/forums/lighting/85667-par-data-spiral-power-saver-bulbs.html

In there somewhere this guy has some amazing non-CO2 tanks.

He says "In my non-CO2 tanks, the HC really grows thick in about 60 umols/m2/s of light (PAR) - and that's measured at the bottom of the tank where the HC is growing. So in the graphics above, any setup that shows PAR values in a range of 60-70 should be "sufficient" light. It doesn't mean you can't go higher. But in going higher, you may be over driving your soil's ability to provide enough nutrients."

"In my non-CO2 tank with an average of 60-80 umols/m2/sec, I never change the water, I dose nitrates-phosphates-traces each twice a week, I have a soil substrate"


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## orchidman (Dec 15, 2010)

thanks alot! i just took a look. and will have to wait until tomorrow to read the whole thing. hopefully my answer will be in there. thanks alot! 

maybe ill go with 60, idk. i just want something that gives good growth without needing to have co2 and ferts.


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## Hoppy (Dec 24, 2005)

We know that many people use the Coralife 2 x T5NO light on their non-CO2, 55 gallon tank, and we have a few PAR measurements with that light, so we know that those people are getting around 20 micromols of PAR at the substrate. From that I think we can safely say that 20 micromols is low light, perhaps a bit less is still enough, but not much less.

We also know that Tom Barr uses 40 micromols at the substrate, with good CO2, to grow any plants he chooses, but slowly. So, I think it is safe to call that medium light. Some people do well with 100 micromols at the substrate, with good CO2, good fertilizing, and lots of attention to the tank, with fast plant growth. I was in that range for awhile, and had to prune about twice a week. That has to be high light. How far the "high" light range extends downward, I have no idea. Nor do I know how big the "medium" range is. In reality there are no discrete ranges, but just a continuum of light intensities, with CO2 needed more surely the higher you go in that continuum.

I would say that continuum extends from 20 to 100 micromols. 

Making this a lot more complicated is the fact that a tank with 20 micromols at the substrate, could easily have over 100 micromols at the water surface. And, a tank with 10 micromols at the surface - not enough for plants, right? - could very well grow plants easily if the only plants ever put in the tank were always tall enough to get up into much higher light territory.


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## Rockhoe14er (Jan 19, 2011)

Hoppy said:


> We know that many people use the Coralife 2 x T5NO light on their non-CO2, 55 gallon tank, and we have a few PAR measurements with that light, so we know that those people are getting around 20 micromols of PAR at the substrate. From that I think we can safely say that 20 micromols is low light, perhaps a bit less is still enough, but not much less.
> 
> We also know that Tom Barr uses 40 micromols at the substrate, with good CO2, to grow any plants he chooses, but slowly. So, I think it is safe to call that medium light. Some people do well with 100 micromols at the substrate, with good CO2, good fertilizing, and lots of attention to the tank, with fast plant growth. I was in that range for awhile, and had to prune about twice a week. That has to be high light. How far the "high" light range extends downward, I have no idea. Nor do I know how big the "medium" range is. In reality there are no discrete ranges, but just a continuum of light intensities, with CO2 needed more surely the higher you go in that continuum.
> 
> ...


wow nicely put.


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## BlueJack (Apr 15, 2011)

Rockhoe14er said:


> wow nicely put.


^indeed. Very well put 

Hoppy, does intensity affect coloration in plants? Specifically reds and purples. In your 100 umol experience did you notice plants showing more brilliantly as they got closer to the surface?


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## Rockhoe14er (Jan 19, 2011)

BlueJack said:


> ^indeed. Very well put
> 
> Hoppy, does intensity affect coloration in plants? Specifically reds and purples. In your 100 umol experience did you notice plants showing more brilliantly as they got closer to the surface?


ooo good question. I really would like to hear the the answer to this question. Also did you seem to get any stunting with 100 um of light and also how difficult was it to provide enough co2 to the tank.


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## orchidman (Dec 15, 2010)

i agree with the above- nicely put hoppy!

i understand what has been said about the ranges, being not known but this is what i gather. 

lowlight- 20
medium light- 40
high light- 100

not knowing where the ranges collide


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## Hoppy (Dec 24, 2005)

I got very frustrated with "high" light, because it was a never ending battle with algae, primarily with BBA. And, several times I gassed my fish with a little too much CO2, losing a few each time. The plants colored up very well, but they also grew so fast that the aquascape only looked good for a couple of days, then more pruning was needed. Eventually I got a little lazy with maintaining it, a chronic problem I have, and the BBA took over the tank. Shortly after that I swore off high light completely, sold off my CO2 system so I couldn't change my mind, and have never missed having high light.

Plants that are naturally colorful will be colored the best when they are healthy and growing well. I don't believe that high light is necessary at all, but having CO2 may be necessary.


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## cggorman (May 9, 2009)

I can't see being very successful with 60 mms and no CO2. Possible, but terribly finicky.

One of my old setups was exactly that. Flourite, 40-60 mms at substrate and no ferts or CO2. I struggled to get healthy growth. Adding ONLY CO2 to the same setup made it MUCH easier.


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## orchidman (Dec 15, 2010)

i just read that whole thread that someone linked. pretty helpful info. but left me confused. a bit. any idea what kind of par i would be getting with opt 1? the substrate will be PFS with root tabs. 

i have dry ferts, but im not sure how much to dose. in the thread someone linked, the one guy said that he doses 2x a week, and never changed the water. what would i dose to do this same thing. i dont think he specified



cggorman said:


> I can't see being very successful with 60 mms and no CO2. Possible, but terribly finicky.
> 
> One of my old setups was exactly that. Flourite, 40-60 mms at substrate and no ferts or CO2. I struggled to get healthy growth. Adding ONLY CO2 to the same setup made it MUCH easier.


would this be because co2 was the limiting factor?


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## BlueJack (Apr 15, 2011)

cggorman said:


> One of my old setups was exactly that. Flourite, 40-60 mms at substrate and no ferts or CO2. I struggled to get healthy growth.


I can see how that would've been tough without any ferts. Just like people need Macronutrients(protein, carbs, fats), plants need Macro's(N,P,K) too. Using some kind of nutrient rich top soil (flourite is basically clay with some micro's mixed in, no N,P,K initially), or a good fish load or some ferts would've made things easier. For example the guy with the 60 umol/No-CO2 tank used a topsoil substrate, dosed ferts 2 X week and rarely did water changes.

My understanding of plants is they can adapt to different situations. Under conditions where light is plentiful (say 60-70umols) a plant can use less resources to make chlorophyll pigments for capturing light(since it's in plentiful supply) and use more resources for absorbing CO2(good for a non-co2 tank). 

This example is a study of riccia (sorry it's in danish) and the Light/CO2 relationship. You can use lux-par conversion of .0185 to figure out the par.










The top left is a good example of a non-co2/low light tank. At 1400lux=25 par and 0.7ppm CO2. With a growth rate of 1.1% over 2 weeks.

If you just increase the light and keep CO2 at 0.7ppm you can see how at 5400lux=100par it grew at 3.3%. My thinking is the plant is adapting to use CO2 better since light is in plentiful supply and it doesn't need to spend so much energy making chlorophyll pigments for capturing light.

I also found it interesting that at 1400lux=25par, if you just increase the CO2 to 35.2ppm you get similar amounts of growth(4.1%) as the higher light/low CO2 example. My guess is that with plentiful CO2 a plant can spend more resources on making more chlorophyll pigments so that it can capture more light at these low light levels.

How this affects the growth of algae i'm not sure. But I'd lean towards hoppy's advice and say that with higher light you have a higher probability of developing algae issue's. 

If you want a Low maintenance, no-CO2 no ferts tank, I think using some lower light (maybe 20-30par?), and a nutrient rich soil with a decent fish load might work best. Trying to find that perfect balance might be tricky.(that's kinda half the fun though) Just my 2 cents.

Hope someone can fill in any gaps or mistake's I made.


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## BlueJack (Apr 15, 2011)

orchidman said:


> i just read that whole thread that someone linked. pretty helpful info. but left me confused. a bit. any idea what kind of par i would be getting with opt 1? the substrate will be PFS with root tabs.


Do you mean this one?










Somewhere around 50. You can see it's different around the tank. If you want to reduce that you could raise it up 2-3 more inches. I think the one in the example is 3 inches above a 5 gallon tank. Or you could put in a 14w cfl bulb instead of the 19w in the example. Or a mixture of the two.



orchidman said:


> i have dry ferts, but im not sure how much to dose. in the thread someone linked, the one guy said that he doses 2x a week, and never changed the water. what would i dose to do this same thing. i dont think he specified


you could use the fertilator over at APC. Just try and find an amount that will fit in the ranges given. 

http://www.aquaticplantcentral.com/forumapc/fertilator.php

Also, it depends on how heavily you plan to stock this tank and how many fish you're going to keep. I think those recommendations are for heavily planted high light tanks. So you could cut back by maybe half and dose less frequently 1 x or 2 x a week? if you're running something that requires less nutrients. i.e. (Low light/no-CO2)


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## orchidman (Dec 15, 2010)

its going to have 3 otos and a bunch of shrimp. ill use pfs with root tabs. 

i'll keep it the way hoppy recommended in i think his first post on this thread. 

this is how it is now. ill keep it that way. 12" approximately above the substrate


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## redfishsc (Aug 29, 2010)

Rockhoe14er said:


> right now i'm experimenting with around 100 par at my substrate to see if i can get some of my plants to get a bit more red.


After I got my hands on a PAR meter a few weeks ago, I tried this as well. 
And hasn't gone well for me. Unreal algae bloom including BBA. 

Of course I expected this so I'm dosing glutaraldehyde (Excel, basically) for carbon.


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## Dave-H (Jul 29, 2010)

I'm having good luck with around 30 mms at substrate with CO2 and EI. The growth is slow, but healthy and very little algae. I can really see why it's a good idea to use as little light as possible to get healthy growth - why cause problems unless you need to?


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## orchidman (Dec 15, 2010)

not sure if you were talking to me or not, but im shooting to not have to use co2


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## Hoppy (Dec 24, 2005)

The reason for using CO2 is because of the amazing benefits you see very quickly. It isn't a case of using it because you have to. With medium sized to small tanks DIY CO2 is enough to give you most of the benefits, and the initial cost is very low.


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## plantbrain (Dec 15, 2003)

BlueJack said:


> I've used this chart as a general guideline
> 
> 
> 
> ...


I agree, these values a re WAY TOO HIGH.

15-30 is low, 30-50 med, 50-90 is high.
Anything above this, is insane.


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## plantbrain (Dec 15, 2003)

BlueJack said:


> ^indeed. Very well put
> 
> Hoppy, does intensity affect coloration in plants? Specifically reds and purples. In your 100 umol experience did you notice plants showing more brilliantly as they got closer to the surface?


I have some Pantanal and some other red species with excellent color at 40-50micromol

These are considered high light demanding species.

In many pics, you will see intense reds as the plants top out over the water's surface, this is also a non limiting CO2 case.........because the plants have CO2 from air at that point.


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## plantbrain (Dec 15, 2003)

Dave-H said:


> I'm having good luck with around 30 mms at substrate with CO2 and EI. The growth is slow, but healthy and very little algae. I can really see why it's a good idea to use as little light as possible to get healthy growth - why cause problems unless you need to?


Cuz they cannot help but think more is better with respect to light, but do the opposite when it comes to ferts:wink:


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## VeeSe (Apr 16, 2011)

plantbrain said:


> I have some Pantanal and some other red species with excellent color at 40-50micromol
> 
> These are considered high light demanding species.
> 
> In many pics, you will see intense reds as the plants top out over the water's surface, this is also a non limiting CO2 case.........because the plants have CO2 from air at that point.


So are you indirectly saying that ample CO2 is a way to bring out the red coloration and not so much the lighting?


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## BlueJack (Apr 15, 2011)

plantbrain said:


> 15-30 is low, 30-50 med, 50-90 is high.
> Anything above this, is insane.


That may be the most useful piece of information I've read on this forum! Thanks :icon_mrgr


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## orchidman (Dec 15, 2010)

BlueJack said:


> That may be the most useful piece of information I've read on this forum! Thanks :icon_mrgr


Agreed!!

Thanks very much Tom and hoppy!


You can call me Bob


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## teonguyen (Aug 25, 2011)

Thank guys for all the discussion because I have just learned lot of value infos here.


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