A few days ago I noticed this in my turtle's tank:
That is the bottom rear edge of the tank. Bubbles had gotten below (or formed below) the glass. My turtle tends to bite and remove the silicon lining the edges, so it's not surprising something like this happened. Since I took that picture the silicon on the bottom side of the glass ruptured. It's still encompassing the bubbles but with little tension.
Has this happened to anyone else? Should I be alarmed about the integrity of the tank and look to replace it?