Here at Hydra Hot Tubs & Pools we prefer low chlorine in the water, but sanitizer – whether chlorine or bromine – is necessary for eliminating and preventing bacteria, along with keeping the water clear. The Frog @ Ease is a low chlorine system that utilizes minerals such as copper to maintain clear water with low chlorine levels. It is a two part system that comes in the form of a ball: the top half is blue and contains the minerals; the bottom half is silver and contains the chlorine and a dial that ranges from OFF to 4. The higher the number the higher the dosage of chlorine. The setting is dependent on the volume of the water of your hot tub and treats up to 600 gallons. Mineral side lasts four months and silver lasts one month. We sell them as a starter kit, which contains one blue and one silver; and a 3-pack of the chlorine is sold separately. If one were to buy one of each they would have a four month supply. There is less odor than using tablets and both halves of the Frog @ Ease are prefilled. When it is time to replace the silver, it will flip upside down with the silver facing up.