💧 Reduces Total Dissolved Solids (TDS) to "0" : The deionization resin is necessary to reduce Total Dissolved Solids (TDS) to zero in the final stage of an RO/DI system. It uses ion exchange to Filter TDS from water. 💧 Refillable Cartridges : Cartridge caps unscrew to allow for refilling with Max Water bulk resin. 💧 Quality Tested: We consistently provide products and services that meet customer quality requirements. 💧 Why Max Water: We have 15+ years of experience in water filtration industry providing solution with a smile to millions of families across North America. Make Max Water your solution to all your filtration needs. Max Water Deionization Resin used to produce 99.99% pure water, convenient post RO filtration DI unit (RO/DI unit). Excellent in areas with hard water. It will give you 0 ppm TDS, Conductivity attainable less than 0.1uS/cm or resistivity of close to 18MO.