Sick about dark spots on cararra marble shower wall
We have dark "wet" spots on herringbone cararra marble mosaic on shower wall. Kerdi membrane on walls & spectralock epoxy grout.. No sign of water damage from plumbing pipe since pipes were installed months before the tiling took place. Silicone caulk around pipe inlets. I don't see holes in grout or missing grout. But it looks as if water got behind the tiles somehow. Should I rip it out? DH says we have to live with it, but it is making me sick.