Green LED's, yay or nay?

[Grendel0501]

Is there any benefit from having a green LED or two in a array?

I've read conflicting things on the net, some people say they help coloring and growth, others say corals in no way use that spectrum.

 

I see the green on the Vegas and the Radion, but not on the reef breeders.

 

This is for a frag tank, so disco effect doesn't bother me.

 

[evilc66]

It has nothing really to do with coral coloration (there may be some benefit with certain fluorescing proteins but it's minimal at best), but more to do with how the color of the light is perceived by your eye. Cyan and green LEDs help reduce some of the purple tint that you can see with royal blue and neutral white combos. Typically, 470nm blue does most of the work, but it can need a little assistance sometimes. It also makes the light brighter to the eye, as the eye is much more sensitive to green light.

[jedimasterben]

Don't both with higher greens, stick to cyan. All white LEDs have plenty of green, but have very little cyan.

[Grendel0501]

Ok, thanks guys.

[blasterman]

There's all kinds of white papers and guessing on the internet about the effect of non photosynthetic colors (mostly green-yellow) on coral growth, and I think I've read them all.

 

The prevailing theory, and one I would put bets on if I had to is the theory that green-yellow helps a coral regulate photosynthesis via intensity and pigment sensitivity. While blue and violet supply the chemical energy for growth green-yellow help the coral grow adjust to actual intensity levels, which are influenced by depth in the water and competition. Blue-violet alone feeds symbiotic algae, but there's no way for the coral to know if this is a result of too much light or too many nutrients. Add more white light (green-yellow) and the coral can do a better job regulating it's symbiotic guests and if it needs to grow taller or wider.

 

There's plenty of anecdotal evidence this may indeed may be more fact than theory in our reef tanks. 10,000k and 6,500k light sources are sworn by hardcore SPS growers to produce better and fuller growth than bluer light sources, and the biggest difference is simply more green-yellow in the warmer lights. Also note that running royal LEDs only in a tank tends to confuse the day/night cycles of corals. Sudden bleaching with blue dominant light sources, etc. Might all be BS, but it sounds like there's something to it.

 

However, white LEDs of any color temp have bootloads of green already. Neutral LED's have insanely high levels of green. If I had a frag only tank and just wanted optimum growth for the dollar and cared less about color I'd probably get one of those generic 120watt chinese LED lights used from Ebay with 2:1 whites:blue. No optics, very smooth spread for a lot of tank coverage, and cheap. Sucky color that would win an ugly contest -vs- dollar store daylight CFLs, but you don't care about that.