replying to my own post. I have a 15lb canister of CO2 on my tank at home. That is 6,803.88g of CO2. That translates to something like 686.56 2 liter bottles of soda for the equivalent amount of CO2 (by weight). I have had my CO2 running for about 6 months and haven't needed to refill it yet. I have heard that they may last about a year. Here comes the (poor) logic. You would need 686 2 liter bottles of soda to provide CO2 for a year?
