If your carbon filter is designed to pull air thru and out, then you should operate it this way. Pushing air thru a filter that is designed to suck air will greatly shorten the life span of the filter itself.

Either way, as long as the top heat is removed you are fine. The air that comes out, if you unit is located at the top should be vented out and away from the grow area.

It will remove the higher levels of air heat and you need not screw with air cooled reflectors unless you are running dual 1000 watt lights.

a 1000W light with a fan on it does wonders...no need for special stuff...you can still get within 12" of the canopy.

Which is plenty.

But follow the designed air flow your carbon filter was built for.