I had a discusion with the owner of a local paintball store being that when I used to first play, I was using Co2 as my propellent, though now I use HPA (High Pressure Air). Theres many fittings you can get threw mail for the tanks and it can release a slow stream. Like a 20oz tank can last about a week and a half slowly leaking out, and refills are like 5$-7$... Though my plants are "Orchids"..

I was thinking being liquid Co2 turning to its gasous form is fairly cold, I was gonan try to have the air enter the plants grow closet right where my HPS bulb is...