POOL FROG IN-LINE PACKAGE for pools up to 40,000 gallons. The POOL FROG Cycler acts as the "water treatment center" and controls the flow of water through the system. No extra plumbing. No electricity. No extra headaches! The POOL FROG Mineral Reservoir, which contains our EPA registered mineral formula and fits inside the Cycler. The minerals continually replenish themselves for added protection against bacteria, as well as keeping your pool's pH balanced by acting as a neutralizer. One Mineral Reservoir will last the full season or up to 6 months; use two reservoirs for year-round pools. The pre-filled chlorine Bac Pac is then inserted into the Mineral Reservoir dispensing low levels of chlorine for 1-3 weeks. The complete POOL FROG System allows you to cut chlorine use by up to 50%* over standard water treatment programs. The patented Control Dial on the front of the Cycler lets you manage the amount of water flowing through the system. Water is circulated upward into the Mineral Reservoir and chlorine Bac Pac simultaneously. The erosion design of this system continuously dispenses chlorine at a precise low level (only 0.5 is needed). Once you've determined the correct setting for your pool just set it, then forget it for weeks at a time!