# Could Too Much light....



## Solcielo lawrencia (Dec 30, 2013)

Yes.


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## fish jihad (Mar 1, 2014)

After some trial and error, and dead plants... i would say yes.


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## Xiaozhuang (Feb 15, 2012)

Too much light might cause algae isssues, or some plants to out compete others, but stunted growth? Never seen that before, some other parameters must be off... Whether it is moss or java fern, anubias, they grow faster if anything under higher lighting. Whether or not people can keep up with the maintenace and balance against algae is another issue, I even run higher lighting on low tech tanks... You can check out the results for yourself


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## Okedokey (Sep 2, 2014)

Solcielo lawrencia said:


> Yes.


Source? Too high intensity? Too long?


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## Solcielo lawrencia (Dec 30, 2013)

Source: experience, also reading others' experiences. It's an intensity issue, not a length issue (though I've never tested aquatic plants by extending photoperiod.)


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## Okedokey (Sep 2, 2014)

http://www.photobiology.info/Chalker-Scott.html


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## angelcraze (Aug 20, 2013)

Okedokey said:


> http://www.photobiology.info/Chalker-Scott.html


Interesting read, and I did not read it all yet, but is this only referring to 'shade' plants that are subjected to too much light? Are we assuming a high light plant would react the same if they were subjected to a ridiculous amount of light?

I just feel one would have to up the ferts, maybe the Co2, to match the lighting intensity. Or how would one figure the amount of ferts necessary to be 'spot on'. I feel there would be insufficient nutrients to cause the stunting if you set your "gas pedal' so high.


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## imcmaster (Jan 30, 2015)

I am going to follow up with my daughter, who is a plant biologist, however my understanding is that the phenomena of photo-oxidation can occur in any plant. Under practical conditions, I would expect this to be uncommon in an aquarium (where our lights are T5s and LEDs). 
At a high level, there must be a balance between the energy absorbed by the light in the cells, and the amount of energy used up in the chemical process of building up the cell.
If the amount of light energy (high intensity) absorption exceeds the rate of chemical conversion, photo-oxidation will occur putting the cells in stress (The plant must manage the excess excited electrons that are emitted due to high energy light).
This is similar, but not identical to what happens if the proper concentrations of nutrients are not present - the chemical process is not able to keep up and stress occurs.
Plants are highly adaptable and can handle various degrees of stress and can even change leaf shape, texture, etc to adapt to the lighting conditions.
But in summary, if the light intensity exceeds what any plant is capable of processing (in terms of the rate of chemical conversion even under ideal nutrient levels), it will suffer, and in extreme cases die.


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## angelcraze (Aug 20, 2013)

It sounds like there is an actual scientific phenomenon that happens within the plant itself that it cannot accept any more light if it is too high. But in our tanks (with T5 and LED), it is more likely to be that nutrients and lighting intensity are relative.


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## imcmaster (Jan 30, 2015)

angelcraze said:


> It sounds like there is an actual scientific phenomenon that happens within the plant itself that it cannot accept any more light if it is too high. But in our tanks (with T5 and LED), it is more likely to be that nutrients and lighting intensity are relative.


I agree that most of us have reasonable lighting, and it comes down to balancing the light against the fert dosing and CO2 levels.
But if you force excessive light, the problem is that the leaf is in the direct path of the light, and is forced to accept the energy. The energy excites electrons, causes photo-oxidation, and it goes downhill from there.
Lesson learned is to always have that balance and don't assume that more light is always better.


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## Xiaozhuang (Feb 15, 2012)

Sunlight is about 2000 PAR, most tanks have less than 100 at substrate... Unless you're using sunlight, its not your lights causing problems


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## howardryan12 (Dec 13, 2014)

Wow, this certainly blew up in the best way possible. 


Assuming that light at our levels cannot do this, should I attempt to first increase ferts? Co2? or Decrease the light intensity?

(running Finnex ray 2 on a 29 Gal, sitting ~3 inches from water w/ a thin sheet of glass between light and water)


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## Xiaozhuang (Feb 15, 2012)

A tank is more than just ferts + CO2; there are plenty of other variables that affect plant growth - temperature, GH/KH, substrate quality, water flow/CO2 distribution, intra-species competition, trimming and pruning methodology... Don't be too fast to jump to conclusions based on the limited visible/obvious variables.

A pic would help a lot... 

Addendum; have any of you guys visited an aquatic plant farm? Common rotala/ludwigia/echinodorus species are propagated under full tropical sun. Java fern, anubias etc are grown under shade cloth


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## imcmaster (Jan 30, 2015)

Excellent points!

The posted question was a fairly theoretical one, but it would help to see/understand the specific observation of how the plant is not thriving.

Question for Dennis: Are the aquatic farms growing out of water or immersed?


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## Solcielo lawrencia (Dec 30, 2013)

Both.


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## imcmaster (Jan 30, 2015)

I'm hoping this thread continues as a means of education for at least me and the poster with respect to intense light.

The poster also asked if dosing and/or Co2 should be raised. I think the practical answer is that EI is used to ensure that nutrients are never the limiting factor (i.e. you overdose then perform water changes to reset), and that CO2 is often raised to just under the point of fish being gased (ie. you gas your fish, and slightly turn back the CO2 output). But I am interested in the CO2 limit of 30ppm (forced by the fish), when CO2 limits in the atmosphere are closer to 400ppm. So what happens when you are using EI, and have CO2 at max, and then increase the light further? We have seen high light used to keep carpets and stem bushes compact, for without the high light these plants can grow upwards and are leggy. Why do these plants react this way?

I asked a biology major about excessive light. One response suggested that excessive light would suppress sugar creation and stunt growth. But the question was also interpreted as "what happens if you keep lights on too long" - and the answer centered around the importance of an adequate dark period. But I'll circle back on that for clarification of 'intense light'.

I agree that the PAR of sunlight is much higher than what is created by aquarium lights. But I have also seen documentaries where a film crew in the Amazon can not find suitable water to film in because the light simply doesn't penetrate very deeply. I recall them saying that only 5% of all waters in SA allowed for reasonable filming. Our aquariums are artificially very clear. What are typical PAR readings in nature at 20" below the surface? 

In short there are many references to people experiencing stunted growth (or worse) under very high light and in cases the ferts are maxed (EI) and CO2 is maxed. It is not yet clear to me why this happens (understanding it could be factors beyond lighting).


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## angelcraze (Aug 20, 2013)

imcmaster said:


> I agree that the PAR of sunlight is much higher than what is created by aquarium lights. But I have also seen documentaries where a film crew in the Amazon can not find suitable water to film in because the light simply doesn't penetrate very deeply. I recall them saying that only 5% of all waters in SA allowed for reasonable filming. Our aquariums are artificially very clear. What are typical PAR readings in nature at 20" below the surface?


Agreed. I don't see how we could compare our small scale aquariums to a river. How far is the sun from the river's water's surface? How much PAR is lost in the air? I have a new heavily tannined tank, and the plant growth is very much affected by how unclear the water is.


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## Xiaozhuang (Feb 15, 2012)

You can find the data in Tom barr's research papers on his site if you're interested in PAR for natural waters - its more variable than most people think....

Whereas for bushy-growth and compactness - often its about trimming technique and not just the light. Plants need not be stunted when they're bushy (though you can stunt them by over-pruning); you would know by the amount of plant mass that is removed each week during pruning sessions. If you have very high-light, what you get is faster growth and the need to keep up with the rest of the parameters... or you get algae. Higher lighting does allow denser growth because it allows a higher amount of self-shading within plant groups

This is grown in 2 months:









About 120 PAR on substrate - prune every 3-4 days









about 600-800 PAR at the higher end portion of the tank:









Everyone does EI and claims to have high CO2, but the results that appear are always so variable... I call this nutrient tunnel vision from spending too much time on forums. (If the only tool you have is a hammer, everything becomes a nail) There are many other variables at play. I'm often amazed at how people can narrow down problems to a single factor (one nutrient etc), when most issues are complex/linked


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## angelcraze (Aug 20, 2013)

I've seen your tank before, it is amazing! Maybe you can help me with my BBA issue LOL.


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## howardryan12 (Dec 13, 2014)

I can certainly post pictures when I get home later! I can give you the link to my tank specs and different levels as well. That way we can use my tank as a sort of starting ground for experimentation.


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## howardryan12 (Dec 13, 2014)

Pics as promised- 

Also, to get my full tank info, check out my tank journal. 
http://www.plantedtank.net/forums/showthread.php?t=789458&highlight=

1.)Right side of the tank. I just put in the circulator 2 days ago to see if the stunted growth might be due to lack of circulation. In the left picture below you can see the outflow for my filter (ehiem 2217). I'm never sure how much flow is too little/too much. 










2.) This picture shows the amount of growth I had this last weekend. When I originally posted this question I was having zero growth for about a week/week and a half. I left for the weekend (mind you not changing ANYTHING) and came back to a significant amount of growth from my stemmed plants. 










3.) Left side of the tank.










4.) Full tank shot. The is where my pregnant red cherries live right now. 










5.) This is one of my main indicators of growth. This is "Monte Carlo" that I've had for about 4 weeks. I've seen next to no growth coming from it, where people often say it will grow like wildfire with a high tech setup (which I have).


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## Xiaozhuang (Feb 15, 2012)

Some general points; 

If the tallest plants are growing, but the shortest ones are not - chances are your lights are dim

If you're dosing full EI on tank that is not super packed with plants, you can rule out nutrient deficiencies - Usually either light or CO2 is lacking (seems to be both in this case)

The drop checker is an approximation, if you really want to fine tune your CO2 levels, experiment with tweaking it up slowly across many hours while observing plant/fish reaction

Water changes for first 3 weeks or so helps a lot in stabilizing a freshly setup tank

Seiryu rocks will constantly raise your KH in a tank with CO2, so you may need a system to stabilize that/reduce its effects


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## imcmaster (Jan 30, 2015)

As always, I agree w/ everything Dennis is saying!

I'd like to think about the CO2 delivery for a minute. We know that the CO2 ppm in water will stray back to a low amount (3 ppm?) when the CO2 is off; we artificially raise the concentration to 30ppm by injecting. So there is this constant loss of CO2 in the water.
You posted a kH of 4, and pH of 6.6 (CO2 on) and 7.6 (CO2 off). This translates into a CO2 ppm of 30, and 3 respectively. So it seems clear that the effects of adding CO2 are working in your tank (you are probably hitting your desired 30ppm), and your plants should thrive at that level.
But how do you know that CO2 is being delivered to the Monte Carlo at the front/bottom? Where do you take the water from when you measure ph? Can the drop checker be moved to a closer location? Do you see the grasses near the MC swaying? Where is the output of the diffuser in relation to the flow of the water?
I see what looks like lots of CO2 bubbles in the enlarged picture showing the recent growth; do these bubbles exist lower in the tank (by the MC)?
Adding the circulation pump may have changed all of this.
In summary, is CO2 being delivered to the MC effectively?

Also like Dennis said, the light penetration to the MC may be too low, but it would be good to rule out the CO2 first.


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## howardryan12 (Dec 13, 2014)

Xiaozhuang said:


> Some general points;
> 
> If the tallest plants are growing, but the shortest ones are not - chances are your lights are dim
> 
> ...


In regards to the lights, I had always figured I might have too much. I use the 30 " (26" actual) Finnex Ray 2. Using par values from this forum, and using what the sticky notes as "high light", I assumed I had plenty (thus this thread being titled too much light?)

I'll attempt to move the drop checker and see what I get in other locations. 

This tank is 4 months old or so, and I've been on water changes at the minimum once a week if not more. 

Are you suggesting my KH may be high?

Bump:


imcmaster said:


> As always, I agree w/ everything Dennis is saying!
> 
> I'd like to think about the CO2 delivery for a minute. We know that the CO2 ppm in water will stray back to a low amount (3 ppm?) when the CO2 is off; we artificially raise the concentration to 30ppm by injecting. So there is this constant loss of CO2 in the water.
> You posted a kH of 4, and pH of 6.6 (CO2 on) and 7.6 (CO2 off). This translates into a CO2 ppm of 30, and 3 respectively. So it seems clear that the effects of adding CO2 are working in your tank (you are probably hitting your desired 30ppm), and your plants should thrive at that level.
> ...


I do have an inline diffuser I've been meaning to install. Would you think that this would help that? I've also wondered if the diffuser is meant to be installed on the inflow or outflow? Mine is sized to fit the inflow, but Im worried about co2 loss while it makes its way through the cansiter. Thoughts on that?

Lastly, My KH was registering between 6-7 last night, with a PH of about 6.4. This would indicate a co2 level of 75ppm+. My fish were not showing signs of distress, but I would certainly imagine that cannot be good for them.


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## imcmaster (Jan 30, 2015)

The inline is not without some problems. It does go on the outflow (ie. the pump pushes water through it), and may slow down your flow. You may find a mist will develop in the water? Can your CO2 system meet the PSI requirements? In theory if the CO2 is mixed in with the return water it will have a positive effect. I don't know if it will dissolve the CO2 any better than your current in tank diffuser. Do you think you will experiment with it, and how will you know if it makes improvements?

I don't know what to say about the 75ppm (using the chart). There may be other acifying compounds in your tank which are causing a lower pH and adjustments must be made to use the chart correctly. As for the toxicity, the guideline is 30ppm, but this depends on the relative levels of O2. So if your tank is richer in O2, then a level of 75ppm may not cause any distress. But I agree you should raise your ph a little!


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## Xiaozhuang (Feb 15, 2012)

imcmaster said:


> I don't know what to say about the 75ppm (using the chart). There may be other acifying compounds in your tank which are causing a lower pH and adjustments must be made to use the chart correctly.


This is exactly it; you need to take a reference PH by taking a water sample and allowing it to rest a few hours (for CO2 to reach air equilibrium).The KH/PH value chart assumes that there are no other acidifying components in your water, if you are using ADA or buffering substrates, this is instantly untrue. (false positive) As I mentioned before, the only side effect of too much light is algae growth, for plants in aquarium conditions, there is only positive effect


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