controlling heat in attic

hey guys ima be using a 400w hps lamp in a cookltube (the one i built) and exausting the heat from the bulb with a 160cfm fan through 2 feet of ducting u guys think this will be enough or add a 80 cfm inline fan to the other side of the tube blowing air over the bulb and boosting the cfm to 240?

that 160 alone should be plenty...best wishes.