Id do all T5s over halides on that tank... you can just get more light over the tank (unless you go dual 400s, which is overkill) where you want it. a 6x54watt system with quality reflectors (Icecap SLRs) and fans will compete with halides easily. If you really want to melt the softies, go 8x54wattT5 and you can grow SPS on the bottom.