We broke down and bought a 20lb c02 tank yesterday. Not as expensive as I had thought it would be, spent about $100 for filled tank and guages. The husband spent the rest of the evening tinkering with it. My question: (and I'm sorry if I sound a bit dumb on this subject, but I'm concerned about putting too much c02 into the tank and I'm suffering from a bit of "information overload" at the moment) My husband has it set up doing about a bubble a second. Is this sufficient for a 210g?