I figure that I buy the 400 watt hps instead of the 200 watt for more yield. I was planning on buying a 4'' vortex fan rated at 172 cfm I think. Would that be enough fan power to cool down the 400 watt hps light? My grow area is about 2 x 2 x 4. Also there is no place I can vent out to from grow room. My cab sits in a place under the staircase and there are no airways on or out of the area. So I thought that venting to outside my cab but still under the staircase would be good enough. Will it?