CO2 Injection...

[SomethingsFishy]

I'm new to planted aquariums, and I was curious about CO2 injection. I'm planning on planting my 20 gallon. I used to play paintball, so I have a couple 12oz CO2 tanks lying around...can I use those for CO2 injection somehow?

 

[Lateral Line]

Do you have some way of regulating their output? I don't know if the cylinders are compatible with the commercial pressurised CO2 systems - might be, that would reduce the cost involved in such a system presumably.