Calcite filters are used in low pH water to raise the pH level thus lowering the acidic nature of water. These filters use inexpensive calcite as the filter media. While raising pH level, the calcite filter also increases water's hardness level. When acidic water comes in contact with calcite, the calcium carbonate media is slowly dissolved, raising the pH, which reduces potential damage, to copper and other metals found in typical plumbing systems. Periodic backwashing will prevent packing and maintain high service flow rates. Calcite will increase water's hardness, so a softener may become necessary downline of the neutralizer.