I don't use co2 but i've heard it does increase yield no doubt about that. However I've also heard that if you have a good enough air circulation/ventilation..you really don't need co2...but hey don't listen to what I'm sayin..I say get the co2..the more the merrier..ahhaha


Oakland, CA.......The Land of "Grandaddy Purp" sMoKe Up!!!!