I think the point is cooltubes are supposed to be totally enclosed and constantly have air wooshing thru via vent tubing, I think you'd be better off with an squarish airtight reflector, like a Cool Junior, you could leave one side open, but traditionally, you have the hood cooled and a seperate outtake pulling air thru a carbon filter, what I did was had a fan on one side of the reflector blowing past the light, thru some tubing attached to the ceiling and it just ended right next to the carbon filter, sucking the hot air of out of the room.