After reading the article on heavy sand, I went down to my local masonary shop for a bag. No dice on the heavy sand. I asked if had anything else that he thought would work. He recommended i try a bag of black beauty, which is a coal slag product used in the sandblasting industry. Pretty fine stuff and he said it wont absorb water. 100 lb bag was pretty small and only 14 bucks. Any thoughts before i fill up my new bags?