So the general rule that gets thrown around is that a 5 lbs tank can serve 20, 5 gallon kegs. So let's do some math, take the 20 kegs, and multiply that by the 5 gallons per keg (20 x 5 = 100 gallons). Now take the 5 lbs in the tank and convert that to ounces by weight (5 x 16 =80 ounces of co2). Now divide the 100 gallons by the 80 oz of co2 (100 / 80 = 1.25 gallons of beer pushed per ounce of co2). The 60 liter soda stream canisters hold 14.5 ounces of co2 multiplied by 1.25 gallons per ounce, (14.5 x 1.25 = 18.125 gallons pushed per canister) so theoretically yes. But it wouldn't be a bad idea to have an extra just in case.