I built my first DIY co2 system today. I'm using a 2 liter bottle with a yeast solution to generate the co2. The cap has a hole with an air line leading out to the air intake of what used to be a venturi pump on my old protein skimmer. I have this in the tank pushing out the co2 bubbles mixed with water from the tank. Basically it's like running an aerating powerhead with the air coming from the co2 generator. This is a pic of the pump operating.
Any input is greatly appreciated. I know it's not real efficient but hopefully its a start