I'm making a canopy for my 90 thats a basic box style with inset lid. The lid will be fully packed with 6 reflectors. Figureing in the tank rim width and reflectors I wont have much space on the front or back of the canopy for air flow. I am putting in 2-120mm fans blowing to the front across the bulb ends. What I'm thinking about is adding vent slots in the top of the lid but don't know how effective they will be. I'm looking at putting the vents where the reflectors meet so there will be the most open space possible to vent heat. The dims for the vents will be 3/4 x 12 @ 4 slots per side. My next quandry is the tank heating up. I know I can add fan or fans to my sump which is no big deal. I've already started my brain on a fan set up for the sump. So what do y'all think about the venting I've come up with.
