I had a temporary set up of 2 - 54w T5HO Actinic and 2 - 10 K 54w T5HO. Each lamp had it's own reflector and it compared to the brightness of 4 - 65w Compact Fluorescents. If your wanting to go with T5 HO's I would go with 6. The brighter the light the more heat it will produce.