Have you tried to change the nozzle/tip on the blaster? My blaster has several size tips for different size media. Also is it clogging when you are using it or just when you first open the valve? I ask because mine will clog when you open the valve at the bottom of the tank if you don't open the valve at the tip first so the sand can keep moving through the hose when pressurized. I guess it just slams it all in the tip and clogs. Just a thought.