ZeroWater Official Replacement Filter - 5-Stage 0 TDS Filter Replacement - System IAPMO Certified to Reduce Lead, Chromium, and PFOA/PFOS, 12-PackCulligan ZeroWater Filter Replacement Pack: Each filter has an estimated 15 Gallon Filter Life, but filter life can vary depending on water quality. For best results, change your filter when the TDS meter reads 006. Advanced Filtration: Our 5 Stage Ion Exchange Replacement Filter removes virtually all dissolved solids (TDS) for the purest tasting water; Total Dissolved Solids are organic and inorganic materials, such as metals, minerals, salts, and