Dry Rock as a Background?

[MobileGoat]

Hey guys,

I was wondering if adhering base/dry rock on the glass as the background, would be a good idea or maybe not so much. Of course this would be the cut shelf rock, so its flat and smooth on one side.

 

[Gumbies R Us]

I think it can work. However my only concern would be algae build up and trying to keep it clean