I'm removing an above-ground chlorine pool installed years ago by a previous owner of my house. Looking underneath the pool, I found that the sand on which it's resting is a gold/bronze color with a metallic sheen to it. The pool itself is steel, with patches of rust. Does anyone have any ideas about how the sand might have turned metallic? I'm doubtful that it started off that way, as no above-ground pool retailers I've contacted have ever heard of such a thing. Thanks!