I use a CO2 tank and a regulator but for a room that size I would have to recomend that you get a good CO2 generator. You'll also need to make sure your exhaust isn't sucking the CO2 right out of the air and venting it outside. There are many controllers out there that do this.

Laterz
Sativagrowin Reviewed by Sativagrowin on . New Room Hey guys, this is a new room. The first room has 60 clones, and the second has 41 plants. The 41 plants have been veging now for two weeks, I want to know how much longer should I leave them on 18-6 cycle before I switch to 12-12. Also, just some tips, pointers, suggestions, and comments would be appreciated. Rating: 5