Unclear on Coral Color and Lighting Color

jeffww

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I can't seem to find a good source for this but does blue light actually alter the pigment and fluorophore composition in coral or does it only change our perception of the photoluminesence.
 

Ron Reefman

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There are 2 things going on here... assuming I understand your question.

Coral's basic colors will look different under different spectrum of light because it's reflected light. If you don't have the proper spectrum in your light (the light, not the fixture) then the proper color can't be reflected back to your eyes.

Hold something red under all blue light in an otherwise dark room and it will look almost black. That's because there is no red spectrum in the blue light to be reflected.

The other way that corals show color is by fluorescence. This is where the pigment of some corals can take in high energy light (like blue, violet & UV) and use that energy to do a chemical reaction and produce it's own light (fluorescence). That's why under all blue light your corals can show a full range of colors. They are making their own light!

You might also notice that although blue corals do look blue under all blue light (it's reflected), it doesn't 'glow' like the other colors because the chemical reaction uses some of the blue lights energy and therefore can't produce high energy blue light to fluoresce.

And in a tank with a lot of blue light and some white light, you'll have both reflected light and fluoresced light. The higher the percentage of blue, the more the colors are fluoresced colors. The higher the percentage of white, the more the colors are reflected colors.

Does all that make sense? More importantly, does it answer your question? ;);Hilarious
 

Cwentz758

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I guess another question is. If I have a “moonlight” spectrum would it be beneficial to run that with my blues on? Or would the blues out reflect the UV/ moon. (I’m using the RedSea reefled)
 

jda

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There are three things... reflection, color expulsion and then actual color rendering.

Reflection is what Ron described above... more colors in mean more colors reflected. RB LEDs are good at this if the coral already has good color... "black light" look.

Color expulsion is when the coral uses light and then spits back out the light at lower energy... so corals might take in real UV at 380nm, for example, that we cannot see and then spit it back out as violet at 405 nm as a nice pretty purple. A coral cannot use and expel a spectrum range that is not in the input light. This is more noticeable with sources that produce true UV and then the corals really shine in the 400-420 range with both expulsion and reflection. Not many LED fixtures can do this, but some have true UV.

Rendering is when the light waves created actual colorful pigments in the coral for us to see. You need light to show them off, but this is different than reflection. Some of these pigments are used for "sunscreen" and some are just the coral being awesome. You need a full spread of spectrum to render the best color, including some spectrums that we cannot see. The people run blue only find that these colors disappear over time in some corals (not all) - this is true of any light source, but more prevalent with LED fixtures.

Rendering is what most people miss when they use blue only. The rendered colors fade away for them and they can get "dull" over time. Full disclosure that I only really keep acropora and clams (and a few softies that I grow to trade), but spectrum from 350-850nm is helpful and human eyes can only see from 400-700, or so. The spectrum above 700 is good for making sunscreen pigment that has metallic looks and offers some really nice contrasting colors as well as helping corals use their energy effectively through the Emerson Effect. Spectrum below 400 is high energy and can really make the corals sing in the violet and deep-blue range beyond what they can do with just blue LEDs. Results will vary with any different kind of corals since they have different colorful proteins and zoox clades - some corals will react to larger spectrums and some do not care at all.

For the most part, you will do very well if you use daylight to render color in the coral and then blue-it-up to your tastes to show them off. You will need some of both unless you really like the shallow water ocean look with whiter light (most do not). With LEDs, this is easy since you can turn up the daylight during the day. With T5 and MH, they have all of these spectrums in them even if the light looks very blue to our eyes. Again, with just my acropora and clams, the two best LED lit tanks have their panels on 100% all day on all channels and then they make them bluer if outside people want to see the tank... some blue, some daylight.

/tldr
 

Ron Reefman

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The moonlight on any tank is totally useless to the corals! It has no affect on the color of the pigments the coral produces.

Moonlights are 100% for human enjoyment and gratification, just like sunrise and sunset.

Professional scientists working on coral breeding may use a moonlight and they tie it to the phases of the moon. Even then, it very hit and miss as to whether it has any affect.
 

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Some say that you need moonlight if you want corals and fish to spawn, but the real moonlight that gets in nearly all rooms seems to be enough since my fish and acropora will spawn on their own - moreso the fish (I hate it when corals spawn... what a mess). I agree with Ron - it is mostly for you.
 
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jeffww

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There are 2 things going on here... assuming I understand your question.

Coral's basic colors will look different under different spectrum of light because it's reflected light. If you don't have the proper spectrum in your light (the light, not the fixture) then the proper color can't be reflected back to your eyes.

Hold something red under all blue light in an otherwise dark room and it will look almost black. That's because there is no red spectrum in the blue light to be reflected.

The other way that corals show color is by fluorescence. This is where the pigment of some corals can take in high energy light (like blue, violet & UV) and use that energy to do a chemical reaction and produce it's own light (fluorescence). That's why under all blue light your corals can show a full range of colors. They are making their own light!

You might also notice that although blue corals do look blue under all blue light (it's reflected), it doesn't 'glow' like the other colors because the chemical reaction uses some of the blue lights energy and therefore can't produce high energy blue light to fluoresce.

And in a tank with a lot of blue light and some white light, you'll have both reflected light and fluoresced light. The higher the percentage of blue, the more the colors are fluoresced colors. The higher the percentage of white, the more the colors are reflected colors.

Does all that make sense? More importantly, does it answer your question? ;);Hilarious

That makes sense. But does spectrum also affect what pigments the coral make? I see anecdotes of coral sellers growing under 6500k and then coloring them up with blues. Is this true?
 

Ron Reefman

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That makes sense. But does spectrum also affect what pigments the coral make? I see anecdotes of coral sellers growing under 6500k and then coloring them up with blues. Is this true?

Yes... over time. And some only change a tiny bit and some can change a lot. If you get a wonderful hot and sunny Spring day and you go out into the sun, you can turn tan or red, depending on how much sun you take in.

I have a green zoa with kind a an old stagecoach wagon wheel pattern in brown on the oral disk. That's what it looks like where I collect it in the Florida Keys and in my tank if I keep it under lower PAR on the sand. But up on the tall rock in the middle of my tank where the PAR is more than double, the zoa turns kind of a pretty deep sky blue!
 
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