There are 2 FAQ's on making a cool tube have you checked it out yet?

http://boards.cannabis.com/grow-faqs...cool-tube.html

http://boards.cannabis.com/grow-faqs...cool-tube.html
Zandor Reviewed by Zandor on . Ventilation Duct Fan For COOLTUBE Question I'm hoping to use it to make a cooltube for a 400w HPS, alternatively a 250HPS. Will this do? These are the specs: TD 160/100. 2 speed: 2500/2100 v/min. Effect 35/23 W. Decibel 39/35 dB(A). Max. air: 160 m³/tim. Rating: 5