You could cool both 600's with one 200cfm fan, if that does not create a nightmare with running air ducts around.

BTW: 424 cfm sounds like a squirrel cage fan. Do yourself a favor and get an inline one, they run quieter. AND as always consider a speed controller, a larger fan running at 3/4 speed is always quieter then a fan running full tilt.
oldmac Reviewed by oldmac on . Air Cooled Hood, Which In-line fan? Going to be running two 600w hps, both air cooled but having trouble picking a fan. I ordered two 424cfm fans from htgsupply, but they're out of stock. They offered to give me a differant fan for the same price. Its better quality, but only 306 cfm. Is this enough to cool the hps sufficiently? Anyone out there with air cooled hoods, which fan do you use? Thanks for the help. Rating: 5