Corals really don't need any light at all for themselves. The zooxanthellae (algae) they keep for food needs light. The algae that corals use for food use Chlorophyll a & c (not b) and 90% of it is Chlorophyll a. The light that is needed for that Chlorophyll to do photosynthesis is really in the very short wavelengths of blue (400nm violet to 480nm blue) and some, but not as much, in the red (640nm to 680nm). So lots of blue. The red will come from the white leds which make white by mixing Red, Green and Blue into white. You'll get more that enough red spectrum from the white leds. Your eyes see white, but the zooxanthellae see red, green and blue (they don't have our eyes). The white leds also add a lot of other spectrum that your coral and it's zooxanthellae don't need and maybe even don't like. Corals from deeper water never see red, orange or yellow spectrum, and many of them are damaged by them. So they morph and make new pigments to block the unwanted spectrum (like sun tan lotion or sun block for us... we don't like UV spectrum so we block it).
The guy, headlessnwalkn, who said white grows coral is an... expletive deleted. Have you ever seen a chart about how light penetrates water? After about 20'-30' there is only blue and a little green spectrum left. Red is the first spectrum blocked by the water and it barely penetrates 5'-10'.
