I have a problem with my sandblast cabinet, it is new and I can't seem to get it to suck the grit through the gun. I am using Garnet grit that I got with it, it is dry so that is not the problem. I tried putting a baffle plate in above the pickup to eliminate any tendency of the grit to pack tight in the bottom of the hopper, no difference. I emptied the hopper and checked for blockages etc, nothing? I put my finger over the end of the suction tube and pulled the trigger and couldn't feel any suction so I am thinking perhaps it a gun related problem? Any ideas?