Keep your swimming pool water clean, clear, and soft with the Pool Frog 5400 Series Mineral Reservoir. This replacement cartridge is designed for use with Pool Frog Model 5400 and XL Pro cyclers, providing an effective water care solution for pools up to 40,000 gallons. By utilizing natural minerals alongside low levels of chlorine, this system helps maintain high water quality while reducing skin and eye irritation. This item is in open box condition, meaning the outer packaging has been opened, but the mineral reservoir inside remains unused and ready for installation. It is a direct replacement part designed to drop easily into your existing cycler system, allowing you to restore your pool filtration to high efficiency. With simple installation and long-lasting performance, this mineral reservoir helps control bacteria and algae growth for up to six months or a full pool season. Enjoy softer, clearer pool water with less chemical odor and hassle by replacing your worn cartridge with this unit.