Faster Growth with Lower Light?

[Hans-Werner]

Light can never be rated independent of nutrients. If a nutrient like phosphate is limiting coral growth, high light intensities will cause polyps to contract to protect them from too much light. With contracted polyps the coral can absorb less nutrients and calcium which results in less growth. Maybe well expanded coral polyps are frequently more important for coral growth than some ppm more calcium or some degree more alkalinity or some dozens PAR more light.

 

[merereef]

High light, low light, blue light, white light. Seems no one can ever agree on what works best when it comes to lights. Some people blast acros with 500 plus par with leds while others give the same piece with the same light and spectrum150 par and both of them will say that theirs grows the fastest. Then color now every one is saying blue light grows corals way faster while in the days of halides the lower kelvin was said to grow way faster it all gets so confusing.

You couldnt have put this more perfectly... maybe we need @Bulk Reef Supply to run some tests

 

[Dana Riddle]

Notes on effects of spectral qualities.

Effects of Different Spectra Generated by LEDs on Growth of the Stony Coral Porites lobata

Stony coral nubbins (tentatively identified as Porites lobata; see Figure 1) were exposed to light of the same intensity (128 µmolm²sec) but different spectra for 75 days. Growth rates were determined by weighing the fragments periodically with an analytical balance.

reefs.com

 

[Jordan Prather]

Notes on effects of spectral qualities.

Effects of Different Spectra Generated by LEDs on Growth of the Stony Coral Porites lobata

Stony coral nubbins (tentatively identified as Porites lobata; see Figure 1) were exposed to light of the same intensity (128 µmolm²sec) but different spectra for 75 days. Growth rates were determined by weighing the fragments periodically with an analytical balance.

reefs.com

So if I read that right each piece was cut the same size given the same amount of light just different spectrum. And their wasnt a significant enough result to say one grew better then the other. So say for instance especially with like a kessil we can just set it to where it looks good. Say more white during the day and more blue at night and it wont make a huge difference as long as intensity stays the same. Did I get that at least half right lol?

 

[Dana Riddle]

So if I read that right each piece was cut the same size given the same amount of light just different spectrum. And their wasnt a significant enough result to say one grew better then the other. So say for instance especially with like a kessil we can just set it to where it looks good. Say more white during the day and more blue at night and it wont make a huge difference as long as intensity stays the same. Did I get that at least half right lol?

Correct.

 

[merereef]

Correct.

Ive noticed some coral farmers include very high greens as close to the white percentage in fact... im guessing the graph below shows that this spectrum was the BEST for coral growth and colour?

 

[Jordan Prather]

Correct.

Awesome thank you makes me feel alittle better now I just need a par meter to get intensity right.

 

[jda]

If you have all of your other "stuff" together, then more light will lead to better growth to a point. Each coral is different. I keep mostly acropora and clams, but I do also have OG Bounce Mushrooms, Colorado Sunbursts and a few kinds of nice/rarer Z*P and even these softies grow faster with more light than less... again, up to a point.

I also think that quality makes a difference and I full believe that every bit of spectrum from 350-850nm is important in different quantities from the high-energy true-UV all the way to IR for Emerson Effect.

 

[Reesj]

Correct.

So @Dana Riddle,
Do you think I can load up on normal blues rather than Royal blues to get almost the same result in terms of coral growth ?
I'm asking as my tank roof does not give me much space to put even proper custom lighting. So I'm atm making do with clip on light strips and they do not come in royal blue(Or atleast dont have it here).
So my main light atm is about 2.5:1 ratio of blue LED to Cool White.

 

[Dana Riddle]

So @Dana Riddle,
Do you think I can load up on normal blues rather than Royal blues to get almost the same result in terms of coral growth ?
I'm asking as my tank roof does not give me much space to put even proper custom lighting. So I'm atm making do with clip on light strips and they do not come in royal blue(Or atleast dont have it here).
So my main light atm is about 2.5:1 ratio of blue LED to Cool White.

Based on what I know -which admittedly isn't much - I think so. While there are differences in adaptability of zoox clades to light intensities (there are 'sun' and 'shade' types, if you will), the photosynthetic processes are basically the same when looking at spectra. So, I tend to think the results of the procedures with Porites corals is applicable to other corals and their zoox.

 

[Stigigemla]

From about ten Years ago (or more) I red of coral farmers that were growing their corals under Iwasaki 6500K MH light.
In order to be able to sell them they were transfered to more blue T5 light for a few months to develope better colour.

I have a Montipora digitata that seems to have maximum growth at 100 or 150 PAR. It is orange with a hint of brown in that light. But if I place it under 500 PAR it gets a clear redish pink very vibrant colour. But it grows slower under that light.
The light in both cases are "white" leds of about 20 000K.
I had under 1 in nitrate and 0 with a Hanna Phosphourus checker.

 

[Reesj]

@Dana Riddle,
So if it was your tank and you had to choose between 60W of blue white combination (even pure blue) or 22W of royal blue and UV which one would you pick ?
Considerations is that Currently have about 70W of light (50blue 20 white) giving around 50-100 PAR. No acros ofc.

I would loved to know what others do i na similar spot. Please give which way would you choose in a situation like that..

 

[Dana Riddle]

@Dana Riddle,
So if it was your tank and you had to choose between 60W of blue white combination (even pure blue) or 22W of royal blue and UV which one would you pick ?
Considerations is that Currently have about 70W of light (50blue 20 white) giving around 50-100 PAR. No acros ofc.

I would loved to know what others do i na similar spot. Please give which way would you choose in a situation like that..

I'd go with 60w blue/white option since it will make the fish pretty. Same if it is strictly for photosynthesis.

 

[merereef]

I'd go with 60w blue/white option since it will make the fish pretty. Same if it is strictly for photosynthesis.

I guess this means it may NOT be a good thing to just run blues all day

 

[Dana Riddle]

I guess this means it may NOT be a good thing to just run blues all day

There's a local coral shop (a good one) that runs their Radions with only blue light from 11 am to 7 pm, with blue/white light from 7 am to 11 am. I tried running only actinic lights on a 110-gallon reef back in the late 90's and had a massive diatom bloom after a few days. Was the blue light responsible or merely a coincidence? I'll never know since I went back to metal halides and never ran a blue-only spectrum again.

 

[Anchor]

Notes on effects of spectral qualities.

Effects of Different Spectra Generated by LEDs on Growth of the Stony Coral Porites lobata

Stony coral nubbins (tentatively identified as Porites lobata; see Figure 1) were exposed to light of the same intensity (128 µmolm²sec) but different spectra for 75 days. Growth rates were determined by weighing the fragments periodically with an analytical balance.

reefs.com

Based on 75 days... there is no significant difference statistically.. Has this been done for a longer period by chance? though the graph by light source does not show significance at 75 days, could it show significance over a much longer period of time, say 180 or more days?

This may not show a difference for fast starting a coral, but creating colonies perhaps? Looking at the 6500K and custom in particular.

I can see I am going to have to go back and re-introduce myself to lighting spectrum from doing plants from 10 years ago.

 

[Dana Riddle]

Based on 75 days... there is no significant difference statistically.. Has this been done for a longer period by chance? though the graph by light source does not show significance at 75 days, could it show significance over a much longer period of time, say 180 or more days?

This may not show a difference for fast starting a coral, but creating colonies perhaps? Looking at the 6500K and custom in particular.

I can see I am going to have to go back and re-introduce myself to lighting spectrum from doing plants from 10 years ago.

Perhaps someone else has conducted an extended experiment. The procedure went as long as it could as calcareous algae was starting to grow on the ceramic plugs at 75 days.

 

[Reefahholic]

@Dana Riddle I have observed a lot of tanks both in person and on video. I’ve personally ran my tanks with both intense light and lower light. With intense light (we’ll call it 400+ PAR) the corals grew short, stubby, and bushy, but had vibrant colors.

In the lower light (120 - 200 PAR) the corals grew much taller and we’re able to grow out more. Monti’s grew more horizontally. A coral being shaded under my overflow box on a frag rack outgrew the side in 500+ PAR. I’ve observed the same in nature. Plants grow shorter, but have more intense color in higher light. I think your study in Hawaii was very interesting. Like you, I do not believe that most corals want/need intense light. Of course they’ll put out “pretty” protective color pigments, but why would they need protective pigments if they’re happy? In my new system I’m going to run at about 200 PAR for a while to see if it outperforms my last tank that was running at 400+ PAR. Despite the nutrients being dosed to that tank and a ton of nutrition going in…many corals did not like the strong light. I saw better growth and health from corals lower in the tank than those at the top. I think corals can indeed be over lit which slows down their growth. I want to post a pic below and you tell me if this coral looks happy in 500+ PAR. The answer is . Look at the tissues. They were basically being boiled from the strong light.


Quick question, if you set up a tank today…what PAR would you personally shoot for?

 

[Dana Riddle]

Peak PAR at the sand bed is ~200, 400ish at the top coral. Matz did a study that showed 'coloration is cheap' - it doesn't cost the coral much energy.