Hey guys. Total newbie here. Used to growing aquatic plants. So I have a closet around 4'x5'x12'. The only exhaust is a grill on the top of the wall around 2.5'x2.5'. How do I make the inlet and outlet odorless? I was thinking of making an activated carbon screen of an inch thick and closing the whole exhaust area with it. Then using 1/3 of that exhaust as outtake and remaining as inlet. Would that work? I also have pressurized CO2 from my planted tank's setup. If I ever want to do CO2, Would I need to make changes to my exhaust system?