When you use things like these as decor do you have to worry about the weight of them breaking the bottom of the tank. I have tanks on those metal stands that you can put two tanks on so there really is no support for the glass on the bottom of the tank. The frame of the tank sits on the stand not the glass. I know to place water or anything in them gently but would like to try some larger stones for decor but worried the weight will break through the bottom.