That's quite easy to check for a leak. After CO2 has gone off, close your main CO2 handle and make a note of the tank pressure. If not the same many hours later, you have a leak. Before I installed my CO2, I tested mine like this and pressure stayed at 800psi for over a week.When I took the regulator off the nut didnt feel that tight so maybe I had i leak from there?
1. Turn off solenoid.
2. Make sure FE handle is depressed.
3. Read & note main tank pressure, about 800psi, or mark dial with permanent marker.
4. Release FE handle to turn off CO2.
5. Leave say 24hours, overnight, a week etc. The pressure should stay 800psi, unless you have a leak. Mine stayed at 800psi for over a week.
Cause found, you have a leak. Problem now is to find it. PTFE tape is OK with CO2, but shouldn't really be needed🙄 . See if you can get a replacement washer, must not be rubber or fibre (fibre is fibre coated in rubber) as CO2 will dissolve in rubber.Tried this a sure enough the pressure went down over night,..