i dont know how a 4" would cool a 1K HPS. I get the plants within 12 inches and dont have any residual heat from the light. Another guy Doco on here uses a 6" as well, along with a speed controller to lower it. The filter will reduce the amount of air the fan moves, so remember that. I wouldn't risk all my plants over a few bucks. I have a speed control and it lets me dial in the exact amount of air i want to move. I can tune it to use the light as a heater during these cold nights here in cali.
dusto2k3 Reviewed by dusto2k3 on . new grower seeking advice sup guys,,, i have a Q for ya'll a buddy of mine just bought a HydroHut, the original size (52" x 52" x 7' tall) it was kind of expensive so i'm lending him my air cooled sun system reflector my Q is.. what size extractor fan should he get so that it will effectively pull air thru a carbon filter, thru the hood, and out the top of the hut??? Rating: 5