# Anybody know what the symptoms of too much light are in aquatic plants?



## jpappy789 (Jul 28, 2013)

I don't think you have too much light, honestly. I've put more over a 10g with CFLs. Likely there's a deficiency elsewhere.


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## Seattle_Aquarist (Jun 15, 2008)

Hi Django,

I agree with jpappy789, it is likely to be a deficiency; some information about your water parameters and ferts may help.


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## FlyingHellFish (Nov 5, 2011)

Beside the fact that you will get deficiency because the Co2 and nutrient demand will go up, there is limit on how fast the plant grows. You will just be forcing it to take in nutrient for storage which there also is a limit.

So let say you some how got them the Co2 and nutrients that they need, you will eventually end up with toxicity of x element. The faster growing plants tolerance this problem easier than slow growing one.

Don't worry though, you will never get to that point unless you try to induce toxicity.

Oh and an example will be iron deposit on the leaf, I read that in a book, which was in a pdf file format, which I got for free, from some pirates at the dock of the bay.


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## Noahma (Oct 18, 2009)

FlyingHellFish said:


> Beside the fact that you will get deficiency because the Co2 and nutrient demand will go up, there is limit on how fast the plant grows. You will just be forcing it to take in nutrient for storage which there also is a limit.
> 
> So let say you some how got them the Co2 and nutrients that they need, you will eventually end up with toxicity of x element. The faster growing plants tolerance this problem easier than slow growing one.
> 
> ...


And on top of this, you might not be able to fulfill the plants fert. requirements and do nothing but cause the plant to die, and algae to envelop the entire tank


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## OVT (Nov 29, 2011)

The plants get red.

via Droid DNA Tapatalk 2


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## acitydweller (Dec 28, 2011)

10wattt cfl's?

make sure these are daylight 6500k bulbs, which usually come in 13w and 26w varieties. Having the incorrect spectrum often will exhibit algae or other problems.


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## denske (Feb 20, 2013)

OVT said:


> The plants get red.
> 
> via Droid DNA Tapatalk 2


This


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## Seattle_Aquarist (Jun 15, 2008)

acitydweller said:


> 10wattt cfl's?
> 
> make sure these are daylight 6500k bulbs, which usually come in 13w and 26w varieties. Having the incorrect spectrum often will exhibit algae or other problems.


Hi acitydweller,

There are 10 watt CFL's in 6500K. I use them myself.


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## Django (Jun 13, 2012)

I'm thinking that maybe 2 10w CFLs is a bit too high for the ferts the tank is getting. I have a gravel substrate, light height of 11-1/2 to 12". I dose Flourish Comp and a few Root Tabs, and once in a great while some Potassium if I see pinholes on leaves. No P or N except for what is in the fish food.

Is it possible that the plants aren't really getting enough ferts? Particularly those Pygmy Chain Swords? What level of ferts should I dose? Remember, this is a 10 gallon tank.

BTW, I've been thinking about a way to raise the bulbs. I'm thinking of making a box frame to sit on top of the tank and allow raising up to 8". Can't go into the ceiling. Thanks for reading.


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## JeffyFunk (Jan 10, 2011)

Tom Barr has previously mentioned that with increasing light (measured by Parr), the rate of plant growth increases with increasing Parr and then starts to level off. In other words, there is a point where the rate of plant growth no longer increases with increasing light intensities, assuming you are able to keep up w/ the increased nutritional needs of the plants so that light intensity is always the limiting factor (the plant growth rate was as measured by mass of trimmed plants). I would think that additional light above this value is what would be considered 'too much light'. At the substrate level, i believe the rate of growth started to slow down above 150 parr. (How that translates to your light setup, i have no clue). 

More likely than not, at increased light intensity levels, you will start to run into nutrient deficiencies, not light deficiencies (esp CO2).


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## Hoppy (Dec 24, 2005)

"Too much" light won't harm the plants, until you get into ridiculous levels of light. But, you very likely will be driving the plants to grow so fast you can't fill their needs for CO2 to fuel that growth. Then, only the most aggressive plants will grow well, and the less aggressive ones will stop growing, attracting lots of algae. "Too much" light is that amount that makes you work harder than you want to to maintain a relatively algae-free tank with all healthy plants.


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## Django (Jun 13, 2012)

Yeah, I just switched gears for a moment to the ferts needed for a given amount of light, where I'm not dosing NPK. I've been told that I don't need NPK in a 10 gallon tank, and I've read that it's too difficult to get the small amount right. I'd appreciate any opinions <img src="images/smilie/icon_smile.gif" border="0" alt="" title="Smile" smilieid="1" class="inlineimg" /> Water test results will be forthcoming. I know that GH is around 5 and KH is around 3. Thanks.


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