Yeah, all good ideas. I just found another fan thats twice as powerful for just another 5 bucks, 720m3/h which I think is around 430CFM, so I'm going to carefully lift mine down on monday, I think its still looking good enough to return in its box, and get the other one:

http://www.swedish-growsystems.se/we...dish/13007.gif

Thanks for all the input guys though, I hope this one will improve things.