This ResinTech water softening resin replaces bad resin in all major brands of water softening systems. The 8% cross link resin balances high strength and high efficiency for the most versatile and popular type of softener resin in use today. One half a cubic foot of resin has 16,000 grains of capacity. This resin is ideal for homes or businesses on city water supplies and for well water with less than .5 ppm of Iron. This resin is USDA, NSF, FDA and WQA approved.