Potable Corrosion Inhibitors can offer the following advantages over a calcium carbonate stability (Langalier) program:   Sequester Calcium and Magnesium, inhibiting scale formation both through sequestering and crystal modification.   Sequester iron and manganese, eliminating "red" and "black" water and the stains and complaints associated with them.   Provide better passivation of all metallurgies, reducing corrosion rates on iron, copper, and brass.   Passivates lead and copper, promotes the formation of a stable lead compound, hydroxypyromorphite, one of the most stable forms of lead.   Provides cleaner distribution systems, helping to remove bio-films and old corrosion products that have accumulated.   Can reduce chlorine demand if applied correctly by removing the metals as part of the chlorine demand.   Can be very cost effective to use if all the benefits are included in the analysis.