for a 90g, 250w DE or 400w SE times 2. Then add the other actinics later. Your old setup is probably power compacts which start to go south after as short as 3 months. I recommend double ended metal halides for the length of the life of the bulb. Other than that you can do T5.

The wisest advice I can give, is do not try to fry your brain looking at home depot ads wondering why you cant use their metal halides instead. You can find some GREAT lighting rigs here for ALOT cheaper than new.