Ahhh!!! Another pool season starting. The cover is off the pool and the water is circulating. I've noticed that I'm missing a set of tiles just below the coping. Either when the water clears enough or if I could find the spares I will need to replace the tiles. Here's the question: Should I use the thinset mortar and grout that is used for shower tiles or are pools different because of the chemicals e.g. chlorine that is used in the water? Thanks.