Heres a little known secret how to easily and immediately add Co2 to your garden. Personally, i did it and my girls loved me for it so i thought id share it.
[video=youtube;ild3ZFylamM]http://www.youtube.com/watch?v=ild3ZFylamM&list=LL1EPZ20DP7SrfxWBR8X4rbQ& feature=mh_lolz[/video]
I wouldn't go this route first off c02 needs photosynthesis in order to work in his vid he mentions how he turns on lights for a hr,then turns it off then he applies his carbonated water.
) to funny really
lets looks at carbonated water and c02 actually does in water.
C02 dissolved in water at low concentrations creates carbonic Acid H2Co3 giving you a PH of 3 - 4 so what are you really giving your plants more or less acid video's like that should be deleted lol
to the op C02 systems can become pricey and also are Very Dangerious running these systems will bump your humidity thru the roof.
Also with running C02 systems comes more risk of getting caught when refilling tanks etc don;t think they can;t figure it out they will when you come few times a month to refill lol a C02 tank propane is much more available so i would suggest a burner but then there could be fire hazzards dam if you do dam if you don;t
Good luck