Make sure you treat that fitting (ball end) on your regulator with care. You could put a nick or ding in it and no matter how hard you tighten it down, it will still leak. They only last so long anyway from constantly changing tanks, so you'll want to keep an eye on that.
Easy way to tell if the seal (or anything else) is leaking is to open the valve on the tank, then close it and watch the gauges.
Rule of thumb since I was a kid is to always close the valve on the tank when you are not using it. Tell that to employees who don't have to pay for the welding gasses. Tri mix and C25 ain't exactly cheap when it leaks out over night.
I eventually made up signs and hung them on all of the tanks that explained the procedure on how to check for leaks and to let me know so I could get the equipment repaired.
All of the leaks we ever had were due to a nick, ding or wear to the fitting that attaches the regulator to the tank. I did actually have a tank valve that leaked, but that's 1 out of hundreds of refills over the years, and they honored that.
Excellent points but I took the regulator valve completely off when I was done last time. Must have left the tank valve itself slightly open.
