Quote Originally Posted by Comatose
If you are brining in fresh air, and exhausting hot air, then you shouldn't need to supplement CO2. CO2 is really only needed in situations where you cannot vent for extended periods of time. Just thought I'd let you know that you can save your money
thanks for the heads up. i thought it would be a nice little extra but im in and out of my cab all day checking p.h. and stuff plus i do have it vented. so i will pass on the co2 then thanks again for the heads up