The OP claims that it was 6 grains of sand but then orders a new purge cover to correct the problem. The two have nothing to do with each other. Also those 6 grains would need to be jammed into the hole where the lever inserts into the air tube. Personally I think the problem was that the reg was set up to loose and continued to free flow once purged because of the venturi effect. My Scubapros will do this too with the adjuster all the way out and the lever set to dive.
Have you seen the small HOG purge button I'm talking about? I'm thinking not. AND I'm not blaming HOG, it's my reg and it has always work well, BUT this is a situation that others may not know can happen. The sand was no where near the lever, it was jamming button and preventing the spring from pushing the button back to the normal position. If you haven't seen one, there's no way I can explain it. When you take it apart you'll say, "Oh, that's what he's talking about." The new full-front purge button eliminates the area where the sand collected, therefore preventing THIS problem in the future.
Yep, EXHALING to clear would have been better (in hind sight), but whenever I did decide to use the purge button on some other dive on some other day the free flow would have occurred then. I wonder at what depth that might have happened and if a trusted dive buddy was as near and so on and so forth. THINGS HAPPEN WHEN DIVING... HOW WE HANDLE THEM DETERMINES A GOOD OUTCOME OR NOT.
KINKING THE HOSE... I never have tried it before and had no idea it would work. Necessity is the mother of invention.
maybe these will help... or maybe they'll just produce more comments... either way I hope to redirect back to the ORIGINAL INTENT OF THE ORIGINAL POST...>>> This was a learning situation for me and I wanted to pass it along to others. ALL of the suggestions mentioned here I have already thought of, but I appreciate the reinforcement.
TC