On the 5.5 Gallon I'm not using a dimmer, and for the moonlights I'm using the old ones off my NC. But (this is a long shot) I'm hoping by summer I can build a larger version for my NC using the LED's, and with regards to the dimmer, I'm borrowing a couple grad students from TAMU, to create some kind of programs to be able to mimmic the Solaris setup with the dimming and all.
On the 5.5 I'm going to have the blue LED's on a different circuit from the whites so they can be controlled independentlyusing 2 timers, the blues will be on for a 12 hour period(fans will be running on the same timer) whither the whites turning on for 9-10 hours in the middle of the day, I'm figuring 2-3 hours with the actinics on to simulate my dawn dusk.