So I recently bought a new used keg and finally got my co2 tank filled and just waiting to fill with beer. My question is I wanted to put pressure on and check for leaks. I set psi to 10 and it was like the gas wouldn't stop. I'm guessing becase keg was empty so would have to use a lot of gas to fill it. Should I fill keg with water and try checkin, as to not burn up as much co2 or just let the empty keg fill. Also what is best way to clean system? Keg looks spotless inside so maybe just run little starsan through it or should I really clean it.