The salt water pools are actually cleaner as they are changed daily and even then they do put small amounts of clorine in it to help sanitize it during the day's use. They do have fresh water showers to rinse off. As for heating the pools....engineering. Hard to heat salt water without lots of maintinance etc. Heated fresh water pools are a health hazard to say the least. Look at the hot tubs and they have lots of clorine and special filtration!