they have enriched the roots tricho... it's called HYDROPONICS.
cloud9- I'm not sure of the costs and whatnot of the co2 systems, but I'm pretty sure for the cash it would take to get one going, plus the refills on the tank(s), u could get another light and increase yeilds that way. Maybe get another 250 watter and run the two lights? Just an idea ya know? ...I was thinking about doin the co2 setup a while back, and it just seemed like too much of a pain in the ass to go through for my little grows, 2-3 plants at a time. Another thing that may help a bit, for yeild, is to try to keep everything perfect in the plants environment as much as possible. Temps, humidity, ph, watering, etc...