Corrosion is caused by metals attempting to return to their natural state. Corrosion can be present in many forms, including uniform metal loss, localized or pitting, bi-metallic, galvanic, under deposit, and microbiological induced corrosion (MIC). The process starts when surface irregularities, stresses, or compositional differences result in the formation of a corrosion cell. Once started, corrosion at the anode causes metal to be released into the system or redeposit locally. Pitting is particularly problematic because the local loss of metal can result in thru-wall perforation of piping and tubing