Abstract: An apparatus, system, and method for sanitizing water contained in a pool or a tank, includes a container to hold zeolite crystals that provide a benefit, in a first mode of operation, of removing urea and ammonia from the water as the water passes through the container and the held zeolite crystals, the held zeolite crystals removing the urea and ammonia from the water by retaining the urea and ammonia as the water passes through the container and held zeolite crystals. A switching mechanism permits the held zeolite crystals to undergo a switch into a second mode of operation during which the held zeolite crystals are exposed to a brine solution that reconditions the held zeolite crystals by desorbing from the held zeolite crystals the urea and ammonia that had been adsorbed by the held zeolite crystals during the first mode of operation.