im told CO2 tanks are the best. i've never used any kind of co2 supplement but i hear tanks is the way to go because all other methods don't produce enough CO2 to make it worth the time or money. also with the tanks you have more control of how much is in the room. some one was telling me about these things that look like hockey pucks. you put them in a bucket of water and they dissolve into CO2 and last like 8 hours each. anyone know if these really work or is this just some stupid new thing to attract growers cause it looks cool but a rip off? i hear dry ice also isnt very efficient because the cost. i know some one that says he makes wine and has a valve that releases the pressure into his grow room. seems to me like it wouldnt really be enough. i read adding CO2 is only worth it if your plants are healthy which mine are. i also read you can double or triple your yield with it. i would eventually like to look into getting tanks, but until then, are any alternative methods really worth it? again i have no experience using CO2 for botanical purposes. can some one that does give any advice? thanks!