Here’s a quick and cheap way to save money, especially if you’re running lots of NMR and GC samples. After each tank change simply spray soapy water on all joints leading to and from the regulator. If any bubbles appear then there is a leak and the connection needs to be re-fitted. Pictured below is a recent change of Helium carrier gas on the GC/MS. Note the leaking of gas in the second pic. Beware of overtightening. A “wrench tight” connection will prevent stripping of the threads.