So we have made a fishpond and it has a fountain/ waterfall type thing. Under it is an led back light panel. I have glued a mosaic pattern in some glass and plan on sticking this on the led back light. Anyway my question is this. The mosaic squares are made of glass and glued on to the glass with glass glue. What can I cover the mosaic squares with to make sure no dirt etc gets in between them? I was thinking a dealent of some sort or glue a piece of glass on the front but with the latter it would be hard not to see the glue. Any ideas?