When we went on vacation, I filled a clear acrylic canister with some 'official' Florida ocean water (from the Atlantic) and some real live Florida beach sand so she would have a reminder of home. When we got back, I put the canister on the counter for a few days and it was fine. But we also had a small dish full of beach shells she had gathered over time and we put these in the canister. Unfortunately, since we did that, everything is turning black. The shells (all except for a few which show no sign)are black, and the sand is black for about half an inch below the surface.
Anyone got any ideas?
Kevin