adding Co2 to your rez

I am going to try adding co2 "the yeast method" to my rez. I researched online and got the idea from people growing plants in the fish tanks. So i made a bell diffuser and put the plastic tubing inside ran the hose to a gatoraid bottle where my co2 is. I figure i cant hurt them they need co2 to make food. I dont have the money for one of those expensive co2 tank systems. Any suggestions. and i know this may sound crazy but can you have too much light? i want to add a 100watt hps to my already 4 100watt cfls. for flowering of course. in need of suggestions on that too.

A plant performs what is known as a gaseous exchange, which means it absorbs Co2 and releases oxygen. For this to work effectively o2 has to be absorbed to some degree through its roots, and Co2 is absorbed through fan leaves (mostly). Aquatic plants like you mention are different, cannbis wont benefit from Co2 in the water, also Co2 in water will cause bubbles which release it from the water so it is a pointless thing to do imo.