The Pool Frog XL Pro, uses a Mineral Reservoir in one Cycler and a pre-filled Chlorine Pac in the other, for complete pool care with extended chlorine pac life over the regular In Ground Pool Frog. This allows you to have more fun with your pool and spend as little maintenance time as possible. Pool Frog is the only mineral system with a pre-filled chlorine pac that meets the EPA requirements to lower previously approved safe chlorine levels by up to 50%. With minerals, chlorine use can be cut up to 50%* over standard water treatment programs. This is a very convenient way of reducing chlorine use and hassle. Pool Frog will make you a believer in mineral pool care with water that feels incredibly soft so your skin stays silky smooth. The XL Pro does the work automatically while you and your family experience an endless summer.