Alright all, thanks for all the great advice. It's much appreciated. Just found out today that there's an unexpected development. The fan I thought I was getting (465 cfm) turns out to only be 265 cfm.

Here's the link ---> http://www.specialty-lights.com/736010.html

All in all, I spent 50 pounds and got an agrosun 400w hps with a really nice reflector that's air-cooled, with a protective glass pane (not remote ballast ) a brand new hps bulb, a new mh conversion bulb, the fan linked above and all the ducting and screw plates I need to hold it in. I'm quite happy. The guy told me he had grown enough (only 1 grow!!) and wanted someone else to enjoy it. Stoners sure are nice peeps.

Now for the question. Will this new dayton 265 cfm fan be enough to keep the hood cool with passive intake and a carbon scrubber, or should I add an active exhaust (120mm 100 cfm computer fan) and attach the carbon scrubber to that?

Once again, thanks for the help
manowar Reviewed by manowar on . 400w hps Hi all, New grower here and I a question about my setup. It's box I built thats 3' tall by 2' deep and 3 feet long. That's a totally of 6 square feet and 18 cubic feet. I recently purchased a 400w hps that is air-cooled with ducting. It has an attached ballast and I'm running a 465hp squirrel fan thru the ducting to cool the hps bulb. Now my first question is, will this fan keep my grow box cool enough? If not would some passive intakes (ie2-3 light-blocked holes on the bottom) and Rating: 5