Hmm, I guess the kits I looked at were meant for reef tanks then. Good to know.
So samamorgan, with your suggestion, I'd have the two center blue LEDs on all the time and the cool whites on just for a few hours per day?
Wingo, I think I'll PM you about drivers once I've finalized what I want to do with the lighting.
Also, since I won't be running these at full power, what do people suggest? 1/3 of the full power? Obviously I want to grow plants and not algae...
It's hard to know at what power you would want them. When doing DIY the best we can give you is rough estimations. I would recommend just getting the LEDs, hanging the above the tank at a height that doesnt spill light over it's edge, and just play with the dimmer level over a period of time until you get the results you're looking for.
As for the moonlight/sunlight hours, keep the whites on with the blues for 8-12 hours, blue only on at night. You can keep the blue on all night if you want, or turn them off after a couple hours, up to you.