i have a 400w hps with 3 plants in a small ish wardrobe.have 1x 120mm PC fan suckin air in and 1x 120mm pc fan suckin air out .also in the ductin i have an 80mm pc fan suckin air out (dunno if this helps with the suction)
anyways .im in the uk an its winter so outside temps are low , but
those fans seem to do the job for me with my 400w hps .temps around 60-80 ish

http://boards.cannabis.com/showthread.php?t=46083
JokerDooD Reviewed by JokerDooD on . About 2 Start My First Grow Need Help!!! Ok well today I was looking into lighting cause i have my whole grow box set up. I looked on ebay cause someone said that ebay would be a good place to look. I found this 400 watt light http://cgi.ebay.com/400W-HPS-MH-CONVERSION-Bat-Wing-Grow-Light_W0QQitemZ7735201669QQcategoryZ42225QQrdZ1QQcmdZViewItem If someone could explain what a balast is and all of the components of this light im not sure im gonna buy it but if i get some feedback then i just might go ahead and get it. Im moving into Rating: 5