The AquaFX Whale Shark RO/DI Filter Set is a comprehensive replacement kit designed to maintain the optimal performance of your 7-stage RO/DI water purification system. It ensures your saltwater aquarium receives only the purest, contaminant-free water, essential for the health and vitality of sensitive reef inhabitants. This set includes a 1 micron sediment filter, two Chlorine Guzzler carbon block filters, a 1.4lb bag of USA-made Cation DI resin, a 1.4lb bag of USA-made Anion DI resin, and a 1.25lb bag of USA-made Mix-Bed DI resin. All DI resins are nuclear-grade, virgin quality. These components are specifically designed to fit the bottom six canisters of AquaFX Whale Shark RO/DI systems and are compatible with most other RO/DI brands, though it does not include the RO membrane. Ideal for dedicated reef aquarists seeking to ensure the highest water quality for their marine environments, this filter set offers a cost-effective solution for routine maintenance. By replacing your filters regularly with this high-quality set, you prevent harmful contaminants from entering your aquarium, supporting a stable and thriving ecosystem for corals, fish, and invertebrates.