Currently I have two 5 lb tanks of CO2 I have been using with my 2 tap kegerator. I like to have 1 on reserve so I never run out of CO2. I am building a 3 tap keezer so that I can have up to 5 kegs at once on tap so I figure another reserve bottle wouldn't hurt. Primarily I plan to have 2 kegs on tap in the keezer and a third carbing. Since I want to always have 1 bottle in reserve should I go with yet another 5 lb canister or a larger 10 lb? Currently I go through 1 keg about every 2.5 weeks. Thanks in advance!