i just added Co2 to my room with a propane burner model because i was heating the room and thought why not add the heat with co2...and i liked what i saw for the short time i was there and have received good reports on the progress...but next flower run will be the first one that i will do start to finish....i added my co2 about 4 weeks into the current flower cycle so i am anxious to see a full run!