Thanks for the welcome and the ideas. The canopy that I built does not have fans yet because I'm still in the market to find a power supply for my LED's and fans. I like the idea about the cooling tube, but I think that the tubing material (abs, pvc...) will insulate the temperature differential too much. I like the idea to cut down on evap, though. I would try it if I had room in my canopy that wouldn't interfere with the lights (210 watts of 420nm and 10KK flourescents). Rich.