pH Filters are made with Calcite a naturally occurring calcium carbonate media.
One of the best things about Calcite is that it is self-limiting property. When properly applied, it corrects pH only enough to reach a non-corrosive equilibrium. In summary, under normal conditions, it it does not overcorrect.
Upon contact with calcite, acidic waters slowly dissolve the calcium carbonate to raise the pH which reduces potential leaching of copper, lead and other metals found in typical plumbing systems.
The Calcite bed will have to be periodically replenished as the Calcite is depleted.
The increase in Calcium and Magnesium Carbonate in the water will increase water hardness and a softener may become necessary after the neutralizing filter.