pH is an indicator of the acid or alkaline condition of water. The pH scale ranges from 0-14; 7 indicates the theoretical neutral point. pH Neutralization cartridges act on acidic waters by slowly dissolving the calcium carbonate and magnesium oxide media as the water flows through the filter, raising the pH of the water and increasing the alkalinity. This eliminates the effects of corrosive water and can help to prevent corrosion of piping and fixtures. Aries 20" BB Chlorine, Taste, & Odor with pH Neutralization Cartridges contain Acid-washed Coconut Shell carbon along with Calcor, a unique a blend of Calcite® and Corosex®. The premium grade, acid-washed carbon is pH buffered and works to correct the taste and odor of drinking water be reducing chlorine and organics, while the Calcor lessens effects of acidic water and can help to prevent corrosion of piping and fixtures.