I have a 48" 6 lamp T5 HO, and I have a huge anemone, soft corals, LPS,
and SPS. You should be able to grow most anything with that lamp.
It will be better for the tank, also... when you remove the "lid" on that tank, it will allow for better gas exchange. An open top will keep the tank cooler, remove carbon dioxide, an help stabilize pH.