I'll se if I can shoot a picture. Cameras took a beating in the Bamahas so don't count on it.\n \nMy sand bed looks like crap. When I left there was a little bit of brownish stuff there. Figured it was normal stuff. Came back and not most of my sand is covered with a black/dark grey YUCK. Its not hard and doesn't feel slimey to me. It breaks off in clumps keeping clean sand on the underside. I don't think its cyano, but I could be wrong. Any ideas what kind of stuff this could be?