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Discussion Starter · #1 ·
I know that too much light is bad for plants as well as too little but what I don't know is how much one should target. I realize it depends on the plants but anubia and java fern (which do not require much light also seem more resistant to too much light) so i'm looking for a good balance that is measurable.
 

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Its not that too much is bad for plants but rather an imbalance is bad. Meaning as you raise your light levels you need more fertilizer and more co2. If you have too much light but not enough plants growing in the tank or not enough ferts or co2 to allow your plants to grow, then you get algae.

TL;DR Anyway for a low tech tank growing some anubias and java fern a good number at substrate to shoot for is 25 ppfd/par. Try not to go over 35 in such a tank.
 

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Discussion Starter · #3 ·
yes but what about small sword plants and red plants that are near the substrate - will 25 par be sufficient for them in a low-tech tank ?
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I'm not worried about algae - what i'm concern about is that under intense lights the plants will reject the light and turn white.

Its not that too much is bad for plants but rather an imbalance is bad. Meaning as you raise your light levels you need more fertilizer and more co2. If you have too much light but not enough plants growing in the tank or not enough ferts or co2 to allow your plants to grow, then you get algae.

TL;DR Anyway for a low tech tank growing some anubias and java fern a good number at substrate to shoot for is 25 ppfd/par. Try not to go over 35 in such a tank.
 

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There is no amount of light that is "bad" for plants. What we provide in our aquariums is a fraction of sunlight.

It's more a matter of what amount of light creates the right balance in your particular Eco system with your particular mix of plants.

I know some very successful planted tankers that keep "low light" plants like Anubias/Crypts/Buce in 200+ PAR. But they are exceptional at what they do and have everything else dialed in extremely well.

If you want to keep it simple, something around 30 PAR will work. But start adding stems and that would change things.
 

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yes but what about small sword plants and red plants that are near the substrate - will 25 par be sufficient for them in a low-tech tank ?
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I'm not worried about algae - what i'm concern about is that under intense lights the plants will reject the light and turn white.
I've never seen an aquarium plant turn white because of too much light. I've seen them turn various shades of yellow when they are dying typically from not enough fertilizer.

Algae should definitely be a big concern as its entirely possible to grow so much algae that your plants are completely covered and then die off.

Anyway most plants that turn red need co2 to help them achieve the red color, some also need the right mix of fertilizer to become truly deep red. Other folk say you need certain spectrums of light to enhance the red look once you have the right ferts and co2 as well. Bottom line is there is a lot that goes into getting a plant to turn deep red, simply making a tank brighter is not going to do the trick by itself.

As to will 25 par/ppfd be enough? Well for anubias and java fern.. ya that's good. If you are talking about other plants, then we need to know what other plants specifically. Want to grow ludwigia? Then ya 25 par/ppfd will work fine. I'm doing it with less. Want to grow a monte carlo carpet? Then you are going to want more light and co2 as well.
 

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Discussion Starter · #6 ·
I have a 300+ par light on my 5 gallon tank for 3 months now. Yea I'm testing something. I can tell you for that tank algae is not a problem but i do have a couple of plants turn a bit white. Plants have no algae but there is a bit of algae on the glass - which is fine for this test.

I've never seen an aquarium plant turn white because of too much light. I've seen them turn various shades of yellow when they are dying typically from not enough fertilizer.

Algae should definitely be a big concern as its entirely possible to grow so much algae that your plants are completely covered and then die off.

Anyway most plants that turn red need co2 to help them achieve the red color, some also need the right mix of fertilizer to become truly deep red. Other folk say you need certain spectrums of light to enhance the red look once you have the right ferts and co2 as well. Bottom line is there is a lot that goes into getting a plant to turn deep red, simply making a tank brighter is not going to do the trick by itself.

As to will 25 par/ppfd be enough? Well for anubias and java fern.. ya that's good. If you are talking about other plants, then we need to know what other plants specifically. Want to grow ludwigia? Then ya 25 par/ppfd will work fine. I'm doing it with less. Want to grow a monte carlo carpet? Then you are going to want more light and co2 as well.
 

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I have a 300+ par light on my 5 gallon tank for 3 months now. Yea I'm testing something. I can tell you for that tank algae is not a problem but i do have a couple of plants turn a bit white. Plants have no algae but there is a bit of algae on the glass - which is fine for this test.
Do you have 300 par at substrate or directly under the light? What are you using to measure par?

Any plants turning a lighter color on you are not the cause of the light but definitely the cause of a deficiency in nutrients. To put it in perspective, the sun is around 1600 to 2000 ppfd at noon. The sun is also providing light for plants a lot longer each day than most of us as well.
 

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Discussion Starter · #9 ·
I'm using an mq-510. It reads about 170 on the substrate. The light is one of those black boxes. It could need more fertilizers but i also read somewhere that if you use too much light plants will turn white.
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This tank is not hi-tech. Long story why i put a black box on it.

Do you have 300 par at substrate or directly under the light? What are you using to measure par?

Any plants turning a lighter color on you are not the cause of the light but definitely the cause of a deficiency in nutrients. To put it in perspective, the sun is around 1600 to 2000 ppfd at noon. The sun is also providing light for plants a lot longer each day than most of us as well.
 

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It could need more fertilizers but i also read somewhere that if you use too much light plants will turn white.
That's the problem sometimes. People repeat what they read.

I run over 200+ PAR at substrate. Plants certainly don't turn white.....more like red, orange, yellow, etc. But they are well fed and CO2 is rich.

And not being argumentative, but I know a LOT of people all over the world who run high light. In the real world with real tanks high light does not turn plants white. Where these ideas get started I will never know.
 

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I'm using an mq-510. It reads about 170 on the substrate. The light is one of those black boxes. It could need more fertilizers but i also read somewhere that if you use too much light plants will turn white.
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This tank is not hi-tech. Long story why i put a black box on it.
The turns white under too much light is a terrestrial plant thing. Even then I'm pretty sure its due to a nutrient issue.
 

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Ok. I will try adding more fertlizer.
I'm not sure what the goal is with the overly bright light. But the easiest thing is to turn down the power. You already have the a par meter so you are so far ahead of the game on this one as to be in a different league. Just reduce the output till you are at that more reasonable 25-30 ppfd at substrate. You still need some amount of fertilizer (a normal dosage) in the tank but then at least you are not in the 'special place' of trying to figure out your own fert dosage in a hyper extreme and unique situation of 170 ppfd and no co2.
 

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Discussion Starter · #14 ·
Well as I noted this is part of an experiment. If the strong lights won't harm the plants (several people have claim that it will); then i want to test the effect over a longer period of time as long as algae is not an issue. So far algae as not gotten on the plants (I do have some low tech low light tank that do have algae issues); so i think i will keep it turned up and try increasing the fertilzer. There are a mix of plants in the tank because i am also testing that aspect - probably the most delicate plant is a purple aflame. Anyway i'll give it another 4 to 8 weeks with increase fertlizer and see what happens - last but least the tank does have banna plant, frogbit, water lettuce and red root floaters providing a bit of shade effect in areas.

I'm not sure what the goal is with the overly bright light. But the easiest thing is to turn down the power. You already have the a par meter so you are so far ahead of the game on this one as to be in a different league. Just reduce the output till you are at that more reasonable 25-30 ppfd at substrate. You still need some amount of fertilizer (a normal dosage) in the tank but then at least you are not in the 'special place' of trying to figure out your own fert dosage in a hyper extreme and unique situation of 170 ppfd and no co2.
 

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I've never seen an aquarium plant turn white because of too much light. I've seen them turn various shades of yellow when they are dying typically from not enough fertilizer.
I've turned 2 plants effectively white.
Keep in mind this is in a tank w/ high Nitrates sooo not N starvation.
The first was a floater that I transplanted.. Light was set to that color atm but you can see normal green to the left:
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Colored up normally after placement there.
Plants will adjust chlorophyll content to the light field.

Second plant is "normally" sort of olive and maroon..
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Boosted exposure a bit but was effectively white..

That said both were sort of a one of...
you can prob make out about a doz of my fertilizer guppies..;)


another pale plant but note that it isn't exactly "unhealthy"..
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