I too have a 90gal pentagon shaped - what are your dimensions?
If you have a canopy like I do then here is what I put:
(2) 36" t5 in the front
(2) 24" t5 in the rear
(2) strands of led
lighting weaving inbetween each T5...
The lighting is intense - doesn't feel hot like halides and the bulbs are small so I have room under my canopy