To help narrow down the location of the leak, try the following:1. Locate the small pinhole on the air tube. This hole is the the regulator’s atmospheric vent. Place a piece of clear tape over it and monitor it to see if it lifts. (Regulator O-rings)2. Insert the fill probe and place a small balloon over the exposed end and monitor for the balloon filling slowly. (Fill port O-ring)3. Remove the shroud to expose the muzzle end of the barrel. Apply a balloon here as well and see if it fills. (Poppet)If none of these places reveal a leak, the next step would be to just go ahead and degas and disassemble and replace all O-rings, or proceed in pinpointing the leak by removing the air tube and placing it in the bathtub. FWIW mine finally developed a slow leak last month and it was the fill port O-ring.