[bucmeister]

I release the pressure on the pinch roller, turn off the tank valve, the pull the trigger to release all of the pressure in the gas system at the end of each session. Have found that I have to reverse the process when first starting up to get the gas back in proper concentration in the entire hose. Thought I had once, but figured out it apparently takes longer than I thought to get the gas in full concentration because one time I welded a short bit after a short purge and the weld looked really poor and porous like you describe.