Why is it necessary to use tiles specifically designated for pools, rather than ordinary ceramic tiles? We've got a vintage early 1930's Spanish mediterranean pool we're resurfacing and turning into a salt water pool, and we're told we must use pool tiles. The pool begs for vintage California tile, which is difficult to find period, let alone when limited to pool tiles.

On a related note, I understand terracotta coping is a big no-no, too. Does anyone know of a material that resembles terra-cotta and that doesn't feel fake or man made? If I were to use terra-cotta, I would seal it with Akemi Nano, which is the stone sealant of all sealants -- at least it is to the best of my knowledge.