# Can too much light damage plants?



## kamikazi (Sep 3, 2010)

That does sound like alot of light, am I reading that you have 6 bulbs over it?

As far as if plants can be harmed by too much light I'm not sure, I know if you take a terrestrial plant and but a bulb too close to hit it will turn it brown and kill it. I would suspect it more to do with plants adapting to the Excel or so other factor though.


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## Patriot (Dec 22, 2010)

I only have 4 bulbs


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## anov50 (Feb 19, 2011)

Did you up the carbon, ferts and flow to match the increase in light? More light and you plants will need more of everything else.


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## Patriot (Dec 22, 2010)

I use flourish excel for carbon and some diy co2 but maybe thats not enough. Does flow really hold a factor? I really didn't know that, no I didn't increase flow because my tank is only 20g and don't everthing blown away. Plus i don't know how to. I turned off both 10000k bulbs off for now until I figure this out.


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## Optix (May 31, 2011)

4 T5HO over a 20gal?











maybe if your fixture is 4' over your tank that would work...you probably only need 1 bulb for sufficient lighting on a 20gal


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## jedimasterben (Aug 21, 2011)

Optix said:


> 4 T5HO over a 20gal?
> 
> 
> 
> ...


I was gonna go with more like


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## Patriot (Dec 22, 2010)

Maybe it is much, but i never had a problem like this before. could the two 10000k be the breaking point alone with the 6500k?


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## jedimasterben (Aug 21, 2011)

10kK (lol) is a lot bluer than the plants need, 5,000K to 7,000K is about it, but seriously you have a mega-ton of light over that thing, how many watts are they, and how far are they above the waterline?


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## Patriot (Dec 22, 2010)

Its a 24" Nova Extreme T5HO fixture with each bulb being 24watts, so I would say 96watts total. It sits about 4 to 5 inches above the water.


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## Rich Conley (Jun 10, 2008)

Patriot100% said:


> Its a 24" Nova Extreme T5HO fixture with each bulb being 24watts, so I would say 96watts total. It sits about 4 to 5 inches above the water.


 
The wattage isn't important though.


Those 4 T5HO bulbs with individual reflectors (which I think the extremes have) are probably 2-3 times the light a 96 watt Power Compact would get you. Thats a TON of light. 


like more-than-needed-for-sps-corals-light.


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## sAroock (Oct 26, 2010)

i have a t5 96watts by 20G (4.8 WpG) setup. 

Its achievable, but not advisable. It needs constant tweaking and attention, and if i leave it for a sec; ..........ALGAE BOOOOOM!


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## Da Plant Man (Apr 7, 2010)

It's really impossible to have too much light when dealing with aquariums IF you have the right balance. I have seen a 20g with six bulbs (freshwater). As long as you have a ton of plants, ferts, and co2 your good. However since you don't have pressurized co2, I'm going to have to say it's to much unless you get lots of co2 in there. Also, that twenty gallon didn't have fish because he needed the co2 so high. I would use only two bulbs if I were you.


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## JasonG75 (Mar 1, 2011)

Optix said:


> 4 T5HO over a 20gal?
> 
> 
> 
> ...


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## OverStocked (May 26, 2007)

Too much light will mean that co2 and ferts have to be impossibly high. You are chasing light, and apparently not dosing ferts? 

Using LESS light, more co2, and more ferts, you'll never have a problem. Too much light is ALWAYS the cause to algae, particularly when too little co2 and ferts are used. 

Add to that the obvious deficiencies you are getting from driving your plants too fast from too much light with too little ferts and you'll see it is a bad idea. You have at least 3x more light than you need...


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## happi (Dec 18, 2009)

are you sure you are not dosing too much Excel. this also melts some of the plants, my tonina showed melting within 2 days when i overdosed the excel.


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## plantbrain (Dec 15, 2003)

Patriot100% said:


> Its a 24" Nova Extreme T5HO fixture with each bulb being 24watts, so I would say 96watts total. It sits about 4 to 5 inches above the water.


I use this same fixture and wattage over a 60 Gal tank at over 1 meter from the bottom of the tank and have no issues with "so called high light" foreground plants.


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## Patriot (Dec 22, 2010)

OverStocked said:


> Too much light will mean that co2 and ferts have to be impossibly high. You are chasing light, and apparently not dosing ferts?
> 
> Using LESS light, more co2, and more ferts, you'll never have a problem. Too much light is ALWAYS the cause to algae, particularly when too little co2 and ferts are used.
> 
> Add to that the obvious deficiencies you are getting from driving your plants too fast from too much light with too little ferts and you'll see it is a bad idea. You have at least 3x more light than you need...


thank you for helping me understand that, I will cut back the lights for sure now. maybe not enough co2 is the problem I know i put in enough ferts but definitely not enough co2.



> are you sure you are not dosing too much Excel. this also melts some of the plants, my tonina showed melting within 2 days when i overdosed the excel.


I will also cut back to excel for a week to see if that makes a difference. I know something changed in the equation all of a sudden, I'm still confused because I was using two 10kk, a flora freashwater, and a actinic bulb before with no problems. I really want to invest in a pressurized co2 system. thank you guys for the help and the funny pictures, those gave me my laugh for today.


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## Lugnut (Aug 12, 2010)

Hopefully I am not hijacking but more like lowjacking your thread here by asking this. Besides algae, what negatives would come from too high light not enough nutrients(Co2 included)?


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## Optix (May 31, 2011)

plant deformities as they run into nutrient deficiency


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## Patriot (Dec 22, 2010)

I think I found the problem. I believe the plants have potassium deficiency, I say this because they started getting small holes and turning yellow around the edges and now the leaves are falling off. I been researching and some of the symptoms match. Secondly the plant that is suffering the most is hygrophila corymbosa siamensis which is said to be a potassium hog. I believe when I turned the lights up the plants sucked the rest of it out of the water. does this sound right?


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## Green_Machine (Apr 24, 2015)

I really don't know that answer. But assuming your 4WPG is high, 40WPG must be severe overkill huh?


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