The application of Vapor Phase Corrosion Inhibitor (VpCI®) chemistry, CorroLogic® System is used in protecting tank bottoms against soil-side corrosion has been classically coupled with the use of ER probes to monitor their impact on the corrosion rate data before and after injection. In most cases, ER probes are used as the primary corrosion rate monitoring technique. The VPCI in Combination with Cathodic Protection is best for complete corrosion solution for tank bottom.