Make sure you only use the red bag of black diamond (fine grit) from Tractor Supply. I found that literally every other media clogged the gun or the ball valve on the bottom. I tried strained sand, black diamond black back (medium grit), fine grit pulverized glass, etc.. the only media I didn’t try was the stuff harbor freight sells. But that’s pretty pricey. The red bag of black diamond is like $12.00 at my local tractor supply, and that’s 50lbs. Once you get it working it actually works great!