Newb Light Spectrum Question
- Thread starter BigEZ77
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theatrus
100-mile-commuter
Generally yes. You may get faster growth with certain lights at a whiter/daylight point but coloration is usually reduced.
Ron Reefman
Active member
Most coral we raise have zooxanthellae (algae) inside the polyps. That algae does photosynthesis and that provides most of, but not all of the food for the coral. That algae does photosynthesis best with light in the 400nm to 500nm wavelength (violet, thru blue to almost green) and a hint of red. That will make for well fed coral. The photosynthesis process can run from 4 to 6 hours (maybe even 8) as long as the light intensity is strong enough. Think about where they come from. They have long days even in the winter and from 10am to 2pm they get great sun directly down into the water from above. For an hour or 2 before and after they still get fairly good light but at more oblique angles and therefore somewhat less intense.
Other wavelengths of light, along with the blue and red, make corals produce pigments to protect them from the light. If you go out in the sun for 4 to 8 hours you produce pigments that protect you from the light. Same idea.
So effectively, almost all wavelengths of light can be good for your coral. It's just some are more important than others (food vs color). And some wavelengths may be less useful to the rest of the tank as red tends to be even better for other algae (nuisance algae like green hairy algae) that you'd just as soon not be growing.
Other wavelengths of light, along with the blue and red, make corals produce pigments to protect them from the light. If you go out in the sun for 4 to 8 hours you produce pigments that protect you from the light. Same idea.
So effectively, almost all wavelengths of light can be good for your coral. It's just some are more important than others (food vs color). And some wavelengths may be less useful to the rest of the tank as red tends to be even better for other algae (nuisance algae like green hairy algae) that you'd just as soon not be growing.
ComforablyNumb
New member
According to Kessil...the color you chose is up to you, it will have very little bearing on the corals (if you are using Kessils). In other words, chose the spectrum you like visually, your corals don't care. Intensity is what matters.
According to Kessil...the color you chose is up to you, it will have very little bearing on the corals (if you are using Kessils). In other words, chose the spectrum you like visually, your corals don't care. Intensity is what matters.
ComfortablyNumb, I can't disagree more with this statement...
What one may prefer visually can be very different than what spectrum is most useful for coral growth, color and health. To say that it is the intensity that matters ignores the basic fact that there is a spectrum that is associated with coral growth and coloration.
ComfortablyNumb, I can't disagree more with this statement...
What one may prefer visually can be very different than what spectrum is most useful for coral growth, color and health. To say that it is the intensity that matters ignores the basic fact that there is a spectrum that is associated with coral growth and coloration.
BigEZ77, you may find it helpful to understand how we generally talk about light in the hobby since we tend to flip back and forth between describing light using Kelvins(which is actually a measure of temperature), color, and wavelength/frequency. There is a relationship between them all but it is not generally apparent to newcommers, it wasn't to me anyway.
Color, as our eyes discern it, can be generated by a specific wavelength of light or, a combination of wavelengths that when combined, produce what appears to our eyes as a specific color. So when we talk about 10000k, 20000k 6500k, whatever, we are descibing the overall color appearance of the light from a combination of wavelengths, not a specific single wavelength. 20000k is going to apear blueish, 10000k is whiteish, 6500k is yellowish. We make some general assumptions regrading what wavelength of light is coming from certains kelvin ratings but we can't be sure without looking at a spectral image of the light being produced. two different 10000k lights can have very different combinations of wavelengths.
Ron Reefman notes specific ranges of light wavelengths that are helpful, others refer to kelvin ratings which is description of overall color appearance. Coral growth, as I have read the research, is typcally associated with light in the 400nm - 500nm and 630nm-670nm range which is constsitent with what Ron is saying.
When you ask, "where in the light spectrum would my corals do best", which is a very good question, you are asking a wavelength question. The answer can be different whether you are more concerned about growth or coloration so "best" is a matter of what's most important to you. Of course most of us want both so we try to find a range of wavelengths that produce good color as well as growth while minimizing the wavelengths that are less useful for either of these such as yellow/orange/green.
So in summary, the point I am trying to make is that in my opinion, focusing on the light wavelengths is more useful than focusing on kelvin value.
Color, as our eyes discern it, can be generated by a specific wavelength of light or, a combination of wavelengths that when combined, produce what appears to our eyes as a specific color. So when we talk about 10000k, 20000k 6500k, whatever, we are descibing the overall color appearance of the light from a combination of wavelengths, not a specific single wavelength. 20000k is going to apear blueish, 10000k is whiteish, 6500k is yellowish. We make some general assumptions regrading what wavelength of light is coming from certains kelvin ratings but we can't be sure without looking at a spectral image of the light being produced. two different 10000k lights can have very different combinations of wavelengths.
Ron Reefman notes specific ranges of light wavelengths that are helpful, others refer to kelvin ratings which is description of overall color appearance. Coral growth, as I have read the research, is typcally associated with light in the 400nm - 500nm and 630nm-670nm range which is constsitent with what Ron is saying.
When you ask, "where in the light spectrum would my corals do best", which is a very good question, you are asking a wavelength question. The answer can be different whether you are more concerned about growth or coloration so "best" is a matter of what's most important to you. Of course most of us want both so we try to find a range of wavelengths that produce good color as well as growth while minimizing the wavelengths that are less useful for either of these such as yellow/orange/green.
So in summary, the point I am trying to make is that in my opinion, focusing on the light wavelengths is more useful than focusing on kelvin value.
Luke Schnabel
New member
My tank is a nice blue color during daylight. I would say between 16000 and 18000 kelvin. if you want the coral to grow faster then add more white, but color will not be as great. If you want more color and have moderate growth lots of blue. I'm thinking about raising my white light about 10% to get a great growth for 6months and then turning back down even lower then what I have to get my color back.
ComforablyNumb
New member
Well you can take that up with Kessil then because they claim no matter what color spectrum you choose with the a360we (from 10,000k to 20,000k), it will have little to no bearing on coral development. Are you familiar with their "Kessil Logic" that comes on all their lamps? Apparently you aren't.
Graph showing spectral output of Kessils at various settings:
In other words, no matter what color settings you prefer visually, with Kessils you will always get the correct spectrum for coral growth and development with great output 380nm to 530nm, with the peak coming at 455nm (anything above that range really doesn't do much for corals and is only added on the Kessils for visual preferences of the aquarist with the important blue spectrums maintained no matter the color chosen). What Kessil DOES warn about with their lamps is the intensity. Cheers.
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CStrickland
New member
you can totally just choose your light settings by what your coral respond well to. But it can be also helpful to have a basic understanding of how the coral "eat" light. This series of articles does a good job of explains that http://www.advancedaquarist.com/2014/11/aafeature - that's the first and there's a few more. I didn't really get what people were talking about with spectrums and wavelengths until I understood the relationship between the zooxanthellae and the host. Once I got my head around that, it was much easier to take in new info and opinions about lights because it fit a bigger picture of coral nutrition.
Ron Reefman
Active member
Luke, white light is a mix of the entire spectrum of colors. Or at the very least Red, Green and Blue (the RGB used in stage lighting and old TV sets). The difference between 16000K and 20000K isn't that significant. The latter is a bit more blue white than the former. It is the blue wavelengths that feed your coral and allow them to grow more, not white (again, which is a mix of wavelengths).
I'm not that familiar with Kessils myself. But they are right when they say that the difference between 10,000K and 20,000K isn't that big a deal to coral health. Although the 20,000K is more blue and will therefore feed your coral better through photosynthesis of the corals zooxanthellae.
The discussion of 400nm to 500nm wavelengths isn't the same as discussion of Kelvin ratings.
As for intensity, there are 3 levels to consider. Too low, which means there isn't enough for the zooxanthellae to start photosynthesis, and too high which will 'bleach' or burn your coral (just like we get sunburn with too much light). And then there is everything in between, enough for photosynthesis to start and less than it takes to bleach your coral. In that range you can run more or less blue while still having a 'white' appearance in the tank. The more blue, the better the coral will do. Making the blue look white involves adding green and red. Some red is also useful. Green isn't used in zooxanthellae photosynthesis at all. But some red and green will help the coral to add pigment which gives it it's 'natural' color (as opposed to the colors they may fluoresce under all blue light).
BigEZ77
Member
Thanks. I'll check it out.
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