The FROG Fresh Mineral Water pool system utilizes a patented combination of sanitizing minerals along with a LOW level of chlorine to destroy bacteria. The Mineral Reservoir contains our patented combination of minerals designed to protect your pool water against bacteria as well as help keep your pool’s pH balanced. One Mineral Reservoir will last an entire season or up to 6 months. For year round pools, simply use 2 reservoirs. The patented control dial on the front of the cycler lets you easily manage the amount of water flowing through the Fresh Mineral Water sanitizing system.