Is 5 lb enough? I am planning on just running 1 keg. Or, should I spend the extra and step up to a 10 lb?
It's a little more complicated and local conditions may dictate which way to go. First, you can get many kegs out of a 5 lb'er, but you may save a bundle by going large. In my area it costs $20 to refill a 5'er, but only $25 for a 20 lb'er. Others post their prices tilted in the opposite direction. So I suggest you find out how they will be refilled first...it may be exchange or true refill...and compare some costs. Ideally you want a spare...those little bastards have a habit of kicking on a Friday afternoon before a long weekend. Personally I like to go large. If you search "CO2 tanks" in Home Bar you can find more discussion.
I'll second Ports recommendation to do research on refill rates in town. For me, I can take a 5# to the LHBS to swap for $25, but doesn't do 20#. I can go during the week before 5:30 pm (but I work until 5:30) and get a 5# for $20, 20# for $25 at the local welding gas shops. There is also a hydroponic shop that is open later and on the weekend that will swap a 20# tank for $15, but won't do 5#. Wish I had 2 20# tanks.
I have a 20lb for my keezer and 2 5lbs that I use for closed transfers and keg purging. If you have the space to work with and don't plan to regularly transport the tank, a larger tank will mean you run out less often for refills.
A side note here. Our local Airgas has separate fees for commercial accounts and retail sales. We have a commercial account and on occasion if I do not tell them the account, they will ring up the sale at a higher fee. So open a commercial account. There is nothing magic to it. Just a cc on file, a billing address and some name for reference. They still bill the cc at the time of sale, just at a reduced fee. Cheers
