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Can strong light ruin plants?

3K views 27 replies 12 participants last post by  fablau 
#1 ·
Hello everyone,
I got a new LED light by BML for my 75gl tank a couple of weeks ago:

MC Series - Dutch Planted Tank 6300K - Build My LED, LLC

And even though I use it at just 30% power, some of my Higrophila leaves, at the top, begun to break down and getting eaten by my trumpet snails. Never happened before, it is just with this new light. I know that it is much more powerful of the simple T8 lights I used to have before, but I couldn't expect plants to be so damaged. Look at the pictures below, and let me know your thoughts: can strong light really do that?







 
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#3 ·
I'd say most likely you're low on something now because the stronger light increased the demands for CO2 and ferts.
So the snails are probably sensing that the newer leaves are weaker? Hence the chomping? The light driving faster growth hence resulting deficiency makes sense. Esp with hygrophila.
 
#7 ·
#16 ·
I think I would go along with roadmasters advice. I haven't had my plecos munch on any leaves, but recently I have seen threads with pics with pretty much exactly the same kind of damage and things were pointing to plecos being the cause of damage, not any deficiencies.

From the pics I have seen of assumed pleco damage looks identical to the damage you are showing (except pic #3 might be melting, or just blurred/out of focus).
I know you don't think the pleco is the problem as it may have been fine for a long time and/or you have never seen the pleco sucking on those leaves (it might just do it at night), but do some searches for "pleco plant damage" and even look up "plant deficiencies" to see if this damage matches any (which I don't believe so, and you mention you EI dose, and doesn't appear to be Potassium deficient hole damage, and it doesn't look like the plant is reabsorbing it's leaves, doesn't appear to be traditional melt to me)
 
#17 ·
Unless the light is entirely too intense, the hygro as it grow's upward's would be privy to higher concentration of the gas near the surface and perform better as it grew taller, so might not be CO2 related issue.
Also, EI dosing as per EI formula for your size tank, would seem to rule out most nutrient defeciencies.
You may very well be doing everything right ,and damage is being caused by snail's after the pleco has rasped on the biofilm of the leaves, and thus attracted the attention's of the snail's.
If all plant's are suffering,then my suspicion's are unfounded/wrong.
Are you sure you have Magnesium in your water supply?
Unless you test foe calcium /magnesium separately,the GH test kit does not tell us whether the hardness as measured by GH kit is comprised of largely calcium,,,or magnesium.
I have water from tap that is largely calcium compared to level's of magnesium so I add a bit of Mg (Epsom salt) to my tank in addition to that found in the trace mix.
 
#19 ·
Thank you guys for brainstorming. I will try to take out the pleco this weekend, and see. I have observed the tank all day long and couldn't see that fish in my Hygros not a single time. It would be really weird he begun to rasp on them right when I changed my light after over a year I have this fish.

Anyhow, here is my city water report, magnesium looks ok, am I right:

http://www.mnwd.com/wp-content/uploads/2013/05/MNWD-2014-Water-Quality-Report.pdf
 
#21 ·
I doubt strong light would ruin plants, but I recently reduced my light and it seems to help solve some earlier problems I had, namely A. Reineckii which would sometimes have stunted tips and always have brittle lower leaves which would get long holes like slits, some algae, and deteriorate. I also have vals which disintegrated as well, and with lower light the runners are making a comeback. Not seeing any loss of color in AR or Ludwigia Ovalis either, which is nice. My previous light setup had the BML Dutch XB running about 85-90%, single T8 bulb and two T5HO bulbs. I reduced the BML to about 65-70% (my dimmer has no numbers or scale) and I removed one of the T5HO bulbs. It seemed like under higher light the plants were "driven too hard," like they were struggling to keep up with the massive light and CO2. I also dosed at or near EI levels so I doubt I had a nutrient deficiency, but the lower light just seems to be a little more forgiving. My pH drop is always 1.2+, with mist blowing right on the more difficult plants. I occasionally get a transparent-looking leaf, but not enough to be a problem. I would think, though, that you could run your BML higher than you currently are on your 75 without problems. What spread did you get? I got the 90 degree spread on mine.
 
#22 ·
It is possible that EI still wasn't enough for the light level or co2 wasn't enough. Took me over a year to realize this. I run dual bmls and now run then 40 percent aside from a 2 hour 100 percent burst. I had the same issues you described when I ran them 85 percent.

Since reducing and increasing co2 a tad everything is growing better. Light definitely drives everything and depending on plant types and mass you would have to increase ferts or co2.

Sent from my SM-G920V using Tapatalk
 
#23 · (Edited)
Hello everyone,
I got a new LED light by BML for my 75gl tank a couple of weeks ago:


And even though I use it at just 30% power, some of my Higrophila leaves, at the top, begun to break down and getting eaten by my trumpet snails. Never happened before, it is just with this new light. I know that it is much more powerful of the simple T8 lights I used to have before, but I couldn't expect plants to be so damaged. Look at the pictures below, and let me know your thoughts: can strong light really do that?
Keep in mind many of the plants you buy are farmed under direct sunlight. Your BML light ain't producing nearly that much light. as far as I know intense light will cause some plants leaves to turn reddish.
 
#24 ·
Update: today I measured the amount of Co2 I pump in my tank. Usually I pump 70ml per minute, but for some reason it was lower, I measured 50ml per minute (!!) no idea why it changed, maybe the pressure of the Co2 tank changed? Anyway, I have restored the amount to 70ml per minute which gives me a 1.3 PH drop. Now we'll see.

So.... Can lower Co2 coupled with higher light be the cause of these "melting" leaves issue?
 
#25 ·
After some further research, looks like it might really be damage caused by Plecos, or even Otocinclus!!

Look at this article, even if in German gives you an idea of what Otos can do to Hygros:

Hygrophila Polysperma


I have about 8 Otos in my tank... is it possible that some (or just one) of them discovered my Hygros as alternative food all of a sudden, coincidentally with my light change? As I said, I have never seen my Pleco on my Hygros, but I keep seeing Otos on them.

It could be hard to understand if they have been actually the "cause" of the problem, or they are just now crunching on the damaged leaves. But I have seen them often on those leaves, even when my Hygros were perfect and healthy. Fact is: The pictures shown on the article above correspond exactly to my own Hygros' leaves damage.
 
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