Ok, so I started messing around with it. I think I found that the rheostat that the company sent me is shit. I don't know too much about wiring, but when I took the rheostat off the fan, the buzzing and humming sound went away. So all of the problems were from the rheostat, not from the fan. Does anyone know of a good/cheap rheostat? The one the company sent me didn't work out, for whatever reason. But anyway, now I have an extra rheostat, a functional fan, and some whooshing sounds coming out of my cab, haha. I'll go pick up some insulated ducting today and hopefully solve this problem. Thanks guys.

I'm looking at a fan like this for my grow tent. It's a simple one from HTGSupply. Measures 20"x36"x64". Do you think this model will work well? What size/type filter should I use?