[Pomme]

Do actinics really help sps corals?

Hiya guys i have been thinking about whether to use actinics on my new set-up. As i am going to be using 3 250watt se or 400watt se 20k, and 2 400watt se 10k. Have been wondering whether actinic supplementation would help. As i think the 20k has around the same wavelength as the actinic with them peaking around 420.

Andrew

[scubadude]

Hey Andrew

Im gonna speculate a little here
I think different corals (sps) require different kelvin ratings and some are more forgiving then others. I am playing around with natural sunlight and using different colored shade cloths more blue then black. I have personally witnessed different coloration under different lighting but usually its a whole different system too which could throw the "lighting only theory" out the window

[Ninong]

Originally Posted by scubadude

I have personally witnessed different coloration under different lighting but usually its a whole different system too which could throw the "lighting only theory" out the window

Good point that is almost always overlooked in all the articles about lighting and coloration in corals. Even though lighting has the most direct effect on coloration, other factors have an indirect but obvious effect.

For example, if you were to place identical lighting over two tanks that were identical in most respects but differed significantly in such things as the intensity of water flow and calcium and alkalinity levels, you would not have identical coloration even if you were using frags of the same mother colonies in both tanks.

[Ninong]

Originally Posted by Pomme

Do actinics really help sps corals?

Hiya guys i have been thinking about whether to use actinics on my new set-up. As i am going to be using 3 250watt se or 400watt se 20k, and 2 400watt se 10k. Have been wondering whether actinic supplementation would help. As i think the 20k has around the same wavelength as the actinic with them peaking around 420.

Andrew

Andrew,

You can certainly cover all the bases with a combination of 20,000K and 10,000K. However, fluorescent actinic lamps have an ability to bring out certain fluorescing pigments better than 20,000K metal halides. This is strictly an appearance thing and really doesn't matter all that much as far as the health and growth of the corals is concerned, but there is a slight difference in appearance that is obvious to us. Whether it is obvious to the corals or not is another matter.

[LazyReef]

I say YES! Corals (some) have adapted special pigmentation to convert violet, blues and UV into PAR so why wouldn't they like it. When you take a picutre underwater without a flash, what do you get? A blue picture. Why? Cause their is lots of blue light. I have usee actinics for over 10 years and I say YES! Some corals like Pavona have even used it to reach depths where others simply cannot compete. 110 feet! There any nothing but blue down there.

[Chris Lakies]

Just my $.02. I would have to say I don't know. But I would say the best lighting for most Reef animals would be somthing that contains full sprectrum. My personal belief is that a 10k metal halide bulb is best suited. From there most reef animals can adjust somewhat. But for looks I think that the Actinic 03 spectrum is great (makes corals glow).

[qwiksilver]

Another .2 worth. What do most people use when they set up a softie tank or a deeper reef face tank... blue. It's because blue (sorry for stating the obvious, but I do have a point.. ) penetrates the deepest through the water. There is tons of blue light. Now, when you sit up on the reef and are within the first ten to fifteen feet, it is not as blue.... by perception to us. That's cause there is more of a blend of spectrum (which I know is still obvious). But just because there is light in more spectrums doesn't mean that the coral uses it. It might allow us to see more color, but again, it doesn't have to do with what the coral uses. Using an excerpt from "Aquarium Corals" by:Eric Borneman :
"Taking the requirements for corals further, research indicates that photosynthesis, and hence the calcification rate in corals, is enhanced by providing light primarily in the blue range, and secondarily in the white range. Red and green spectra, despite being correlated with a shallower depth where one would expect to find many corals, do not have as pronounced a positive effect on CORAL GROWTH. Red light has even induced bleaching. Thus, any lighting should optimally be concentrated in the blue and white light spectra. This is a bit of a misnomer, since white light theoretically encompasses all spectra of visible light. It may be more accurate to say that there should be a preponderance of blue-peaked spectra, with the remainder being made up of white, full-spectrum light devoid of sharp peaks or unbalanced spectral characteristics. While a mix of 50% blue and 50% white light has been generally promoted as a good mix of light spectra, I have found that mixes with from 60% to 75% blue light seem to give better results."

HTH