I got one 5 gallon keg from 4 5# C02 tanks. No, that's not a type-o. I have your same problem. I've stripped and re-stripped my kegerator rig 4 times, kegs, fittings, and o-rings. Then spray tested. I can't figure out what's leaking. My beer carbs perfectly, I set it to 12psi and two days...