Hello all. We had a leak in our bathroom and had to redo the base and bottom row of shower tile. The tile we picked for the bottom row matched almost exactly the rest of the tile but upon installation, it turns grey. I had them repeat one tile and the same thing happened. You can see in the photot that the tile installed matches the wall but the next day it turned darker grey (the shower was not used that night). Any ideas what could be causing this? and how to remedy?