Hello! Last week I tried to build a yeast CO2 injection system for my 20 gallons full of plants tank. I mixed together one liter of water, 25 gr of beer yeast and a cup of sugar. It worked (one bubble per second) for one day only. Maybe I used a wrong quantity of components. Does anybody know the exact amount of the components? And what about the yeast? What kind of yeast should I use? Thanks a lot.