Do you have a metal halide already or would you have to go get one? if you already have one or you dont mind and have the $$$ to buy one i'd add it if possible to help the t5s but you should be perfectly fine w/the t5's. is the bloom room the same height? A 600w would be alright, but youll want to cooltube it for sure, dont make the mistake i did and get a duct fan for the cooltube and think its gonna work really great, it will work but they have alot of things that fuck up their cfm. They dont move as much air is advertised, ever really. just spend the extra for a can fan. You want that light as close as you can get it, I can keep my 400w hps about 6-8 inches from the tops now compared to 12-14 inches w/the duct fan instead of a can fan.