Container Soils - Low Grade Perlite

Living in a small rural area makes it especially hard to find just what I want. I finally picked up a large (3 cu/ft) bag of perlite at a garden / farm supply about 20 minutes south of me. It was labeled "Horticulture Grade".

After I got it home and opened it up I found that it was a pretty low grade stuff. Maybe that's what horticulture grade is, but I didn't know that at the time. It was totally inconstant in size ranging from about ¼ inch down to powder. And a lot of powder. I screened it out through a metal insect screen. The photo is the result. About 30% was powder. Disappointing.

I've since found that Home Depot sells medium (or course, can't remember now...) in 3.5 cu/ft bags. The closest home depot is 40 minutes away. I drove. They were sold out. I was upset. Who sells out of something as important as perlite in the middle of February? Oh well.