Providing cathodic devices that protect against corrosion in water storage tanks defers or, in some cases, eliminates the need to recoat submerged surfaces, making such systems economical over the long term. Some types of new anode materials have a design life of 10 to 20 years, whereas aluminum anodes must be replaced annually. Automatic electric current control systems are also available to compensate for fluctuating conditions, to measure the potential in the electrolyte, and to lower the electric consumption of cathodic protection systems.