Would have have been better if you would have created a new thread to get more answers to your question. Four 54w T5 HO
bulbs on a 90g would get you softies and a good portion of LPS
at best. I wouldn't expect much out of 6x54w T5 HO
on a tank that deep either. Would be best if you went for halides or an 8x54w T5 HO
fixture (Current USA makes a NEP that is 8x54w and has lunar LED
's), with halides being the better option. Heat wouldn't be a problem as long as you have proper ventilation.