I had a ton of clogging and other problems until I purchased some good media. It made a world of difference. I was working myself to death trying to avoid clogs, shaking the hose, kicking and rocking the tank, trying different settings. The problem with play sand and most other garden variety sand is that they have clumps in them or the occasional large particle. Even when you strain them they can gang up and cause problems.
I bought some called Black Diamond from Northern tool. I was like night and day and it was impressive how much work I could get done when the blaster was working at high capacity for several minutes.