So i am starting to put together the things needed for a small grow in my new place. I want to use the growlab 60 tent with an air cooled 400 watt HPS. A buddy of mine will give me a great deal on his barely used 4" vortex fan rated at 172 cfm. Do you think this will be enough to cool the tent . or should a spend some more and get a bigger and more powerful fan. btw the exaust vents in the tent are 5" so the 4" ducting will fit as opposed to 6".