I live in Hawaii, my house is hot and I run 2 X 250W halide bulbs and 4 X 54W T5s over a 75gal. Just make sure you put a fan between the fixture and the water surface to cut the heat transfer and you will be fine. I would have to run chiller no matter what to keep my tank at it's perfect temperature range, so I have one. The ATI Sunpower will be the easiest option and more forgiving than a metal halide system in any case, as long as the height of the tank is up to 24". Halides will help the production of some natural pigments that the T5s won't be able to give simply because of the extra intensity and amount of UV emitted. You want to go very easy get the T5s. You will also have great colors and great colony formation!
The main difference, to help you choose is shimmer or no shimmer.
I like both results and enjoy either types of technology over my reefs.
