Mineral purifiers naturally sanitize the water while keeping the amount of chemical additives to a minimum, saving time and money. Chlorine - most common type of cleaning system Frog - Mineral based system that helps reduce amount of needed chlorine Nature 2 - Mineral based system that can be combined with salt water systems Salt System - creates chlorine from salt for a less chemical swimming experience Baquacil - Chlorine-free system that is less irritating to eyes and easier on pool liners.