An air-cooled hood has one 4" or 6" air duct input and one for the output. You install an inline fan to bring air in from outside the grow area through the light and then back out the room taking the heat with it. This way you can get the light closer without burning your plants or getting the temperature too hot and causing them to hermie.

A Cool Tube is the same principle but has a round glass tube that you attach the ducting to and can get much closer.
Zandor Reviewed by Zandor on . noob grower, first system hi, ive just got the idea of growing some cannabis seeds so ive ordered a basic hydro setup. this is it: http://www.basementlighting.com/Merchant2/4.13/merchant.mv?Screen=PROD&Product_Code=HS1&Category_Code= is this anygd, will it do the job i want it 2 do? ive also ordered a 4inch extractor fan, some snow white and ingemars punch seeds, some rockwool and extra nutrients. i shud recieve it all tomoro. will the nutrients which come with that be gd enuff for the plants?. any help wud be realy Rating: 5