The ACR-1 filter series uses FDA-approved resin that reduces the content of calcium and magnesium ions in water. 

Calcium and magnesium are often referred to as "hard minerals". Large amounts of these ions in water are responsible for the formation of deposits, higher detergent consumption, and stains on glass. Hard water damages household appliances such as dishwashers and washing machines and increases energy consumption.

The filter contains a special blend of softening resins suitable for drinking water applications, and can also be used as a pre-filter in reverse osmosis systems to provide protection against excessive hardness in the reverse osmosis membrane.