I think Daisy may be thinking of garden DE which is fine, powder like. That you would not want to use in your soil mix as it will interfere with soil drainage--like fine/playground sand. The Out of Africa website says that they use the NAPA brand. That one has particles the size of aquarium gravel or the large chicken/granite grit. Is my explanation close to what you were expressing, Daisy? Anyway, it's just my 2 cents, and I felt that it's worth mentioning.
