That depends on how big you make your filter. It can be as small as a gallon jug or as large as a laundry basket. It just all depends on your needs. If you are concerned about the fans power, then just make the filter smaller and change the carbon more often. Good luck- Diz:rasta:
Jdzzl03 Reviewed by Jdzzl03 on . Would these fans do the job (400W HPS). Hey, Im planning on building a 5'6"H X 2'6"W X 2'4"L Grow box, im gonna use a 400W HPS light with a Sylvania bulb. Im planning on getting these and having one for active intake/blowing on plants and 1 for cooling the heat from the light. ---> http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=7617002059&sspagename=ADME%3AL%3ARTQ%3ACA%3A1&rd=1 Do you think theyed do the trick? Im also gonna make a Carbon filter for my exhaust. Rating: 5