Originally Posted by Phong
I'd personally go with a retro for the sole purpose of being able to add additional bulbs if you wish. Using a WH5, you can run 2, 3, or 4 bulbs. I'd say start with 2 then add more if you feel its necessary or like in my case, when my budget allows it.
Phong is right on here
I would not use the IceCap ballast on a 12" deep tank-you would likely fry your corals.
I have 2 T5HO (1 ATI Blue+ and 1 ATO Aquablue) on my frag tank and corals are growing fairly well, and 3 (2 GE 6500k and 1 Giesemann Pure Actinic) on my fuge and corals growing very well (I know it's backwards!)
Another bonus to the retro is they are easily used on a bigger tank when you get one.
The ATI bulbs are the best IMO-great color, par value, and the best warranty. The GE are very good low cost/high par bulbs