i use a 4" inline duct fan with a 400 hps and have no issues!!!!!!!!
nemf 2000 Reviewed by nemf 2000 on . Fan for cool tube I just made my first pyrex cool tube for my 250 hps, i got 4" x 36" ducting (including the tube itself) and i was thinking about getting one of these fans, or something similar. http://www.bghydro.com/BGH/Itemdesc.asp?ic=AEFSC04&eq=&Tp= Does anyone think i'll need more?? I don't have lots of money for a blower so that is out of the question, and also if this is enough should I have it sucking the warm air out or blowing air in?? Rating: 5