Closet grow

I have a 2x4x8 closet with a 400 watt hps non air cooled light. i wanted to know the best way to cool the closet. i have a fan that hangs and blows air out the top corner, about a 3x3 opening. any other suggestions?

I had the same set up for years. I just recently changed it. I tried to get away with a non air cooled hood and i couldnt keep the heat down. I went and bought a 6 in air cooled hood and a 6 in vortex fan and that took care of my proublem. I also cut a whole in the wall for cool fresh air to be brought in by a 6 in inline duct fan. My temp stayed from 70 - 80 degres depending on what temps were outside.