These are the reds I'm talking about over on rapid that peak around 660.
In regards to the reds being bad...I don't know what they mean about that. Red you do have to be careful with because it helps to fuel algae growth if nutrients are not kept low. When it comes to softies, they pretty much thrive in the wild off of light in the blue wavelength (deeper waters). Red and yellow don't penetrate far into the ocean at all. But shallow water sps are adapted to receiving light in the red wavelength. Especially the ones in tidal zones that are sometime exposed to air for hours at a time in some areas at low tides.
If you look at the cree spectral analysis sheets the best leds for producing red in the wavelength most important for them they would be...Warm white, neutral white, and then cool white in that order. The cree reds peak somewhere around 630nm when the more important zone for coral is right around 670nm. That's why I like the red led posted above that peaks at 660nm.
The best area of spectrum in the blue wavelength for corals is between 465-485nm. Thats where the royal blues and blues come in if you check out the spectral analysis on those.
My idea isn't to run the reds all the time but have them come on during the day at high noon or the peak of mid day for a while just to give the corals what the other leds are lacking. Otherwise I think the neutrals will be plenty to fill in the other areas of the spectrum for viewing and such.
Yellow and Green areas of the spectrum are fairly useless for coral photosynthesis. But cyano loves that area of the spectrum. Fluorescent bulbs are most notable for producing useless light in those ranges. But it's probably great for fuges. As would be warm white leds.
Here's a good article by Sanjay...
http://www.personal.psu.edu/faculty/s/b/sbj4/aquarium/articles/Photosynthesis.htm particularly the section discussing photosynthesis.
And I like his closing paragraph...
"The ability of the corals to adapt in such an incredible manner also raises some other interesting issues. Should we try to emulate the reef zones in our aquariums and make the effort to try to provide the light spectrum and intensity that the corals are accustomed to in the wild? Or, should we provide light that “enhances” the visual appearance and coloration of the corals and force the corals to adapt in a manner that we find appealing?" (Sanjay Joshi)