I have a 5X5 tent with a hydrofarm air cooled reflector, I'm using a 400mh and will switch to a 600hps, I bought a fan, its a vortex 6" CFM 115v, I hear this fan is best used with a carbon filter, which may be why it cost so much! 215.00 I was told I'm better using a cheaper fan for the light, is this true? if so what type...thanks