You need cooling to run CO² like an AC unit. If you have air-cooled hoods heat should not be a problem. You are correct the CO² would leak out. You need a sealed environment and the idea is to raise the level around 1800 PPm and hold it there for several hours. Evacuate the room with the vent for how ever long it take to exchange 100% of the air and then pump CO² in again up to 1800 PPm and hold it there. Think how you can pipe the air from a window unit AC into your area. What is the RH in your flower and veg area or do you even worry about that?

You could put your exhaust on timmers so they do not run durning the period you are using CO².

NOTE: CO² is worthless if you do not have HID lights, fluorescents do not produce enough light for the plant to process the extra CO². 400w is the minimum light for good CO² absorption.
Zandor Reviewed by Zandor on . Best way to thicken main stem? I've only heard of having a fan blow on them but I'd like to know what you guys think. Rating: 5