Reds, Pro's-brings out colors and can be good for corals in low intensities.
Cons- can fuel algae and hurt corals if to much or to high.
Greens- Pros-99% for visual appeal and should only be used to get the "look" you want.
Cons- can fuel algae growth
This is only my opinion from things I've read and on my Radions I keep my reds about 20-30% and greens are only on a few hours a day on very low. 15-20% at most.
I added 4 greens to my 48 led diy light and it really made the greens in my corals really pop. I havent noticed any increase in algae growth and I run non dimmable drivers. I plan on adding them to my other 2 lights.
Jeff
A quality White LED like the Cree 5 Watt XT-E or XP-G will have plenty of the green spectrum.
In nature corals receive very little if any red. For shallow corals like zoas a little red can help. For growth adding a couple warm white LEDs will have enough red without fueling algae growth.
Everyones tank and corals are different and respond differently to changes in light. I like the use of RGB clusters along with Primary LEDs so you can tweak the colour perfectly to suit your taste.