ISSUE: Blast Cabinet Media

We need more abrasive media for the blast cabinet. I’m happy to buy some, but want to make sure I get the right thing. Anyone know the correct media? I’m assuming it is aluminum oxide, but grit?

Tagging the @Metal_Shop_Team

I am also willing to purchase some media. I was thinking of getting some 12 grit walnut shells. Would 25 lbs suffice for our blast cabinet?