The Scale TAC-ler Replacement Cartridge is designed for use with the Stiebel Eltron Scale TAC-ler or Scale TAC-ler Plus Water Conditioner Filter. It can also be used with most brands of Big Blue 4.5” x 20” filter housings, and many other TAC filters of the same size. The Scale TAC-ler water conditioner is compatible with all tankless and conventional tank-style water heaters. Hard water mineral scale accumulating on heating elements slowly reduces water heater performance. It affects both heat transfer and water pressure. Preventing mineral scale formation ensures your water heater’s optimal performance, increases service life, and possibly prevents premature failure. Scale TAC-ler will prevent future mineral build-up. Scale TAC-ler is installed on the cold water inlet of the water heater, where it treats the water entering the water heater. It will provide protection for flow rates up to 6 gallons per minute. Scale TAC-ler salt-free water conditioners use a specialized polymeric bead medium that serves as a catalyst for the formation of calcium and magnesium carbonate nano-crystals. Instead of forming hard mineral scale on surfaces, these microscopic crystals of calcium and magnesium carbonate remain suspended in the water and pass through to the drain. This process is called Template Assisted Crystallization, or TAC. A university study determined that TAC technology was the most effective of all non-salt water conditioners at preventing mineral scale, with reduction levels consistently in excess of 90%.