Hi Michelle,
we are the manufacturer of the hydrex and protex.
The best selaer for your excotic material is another one called RESINSIL. It is form the same family of the PROTEX and definetly superior to the hydrex and a lot of the competitors.
it was engineered to work on those material that has been reinied at the factory, and the chemical property is such that it will link to the
epoxy resin to create a almost perfect protection.
Now remember also that you are going to appy in a shower, when the water effect is on the stone and the
sealer will effictevely remove day after day part, part of the stone (and the
sealer of course).
you probably saw the effect of running water on "river washed" stone or glass on the beach.
so what i am trying to tell you is that unfortunately, regardless of the
sealer you will choose you will probably have to reaseal the shower every 6-12 months.
Email us if you need more info.