Krieger:they are all just Silica Sand. I use unscented cat litter. Buddy uses Heartfelt beads. We both hold 67-68% year rounds. I paid next to nothing for a HUGE bag... he paid much more, for MUCH less.
BUT, I guess it's piece of mind for some people.
Direwolf:I bout heartfelt and now run @68 %.. I'm happy with that