Zinc-Aluminum Anode Rods

For protecting solar water heater tanks

A sacrificial galvanic anode rod is used to prevent corrosion to a more noble metal. When attached to the noble metal, the anode will corrode before the noble metal will corrode. In the case of a water heater application, the sacrificial anode rod is inserted into the tank and the metal it is protecting, the inside of the tank, will not corrode unless the anode rod corrodes away first.

Anode rods should be checked annually for corrosion. If the rod has corroded a significiant amount, then it should be replaced with a new anode rod. If the anode rod is changed out regularly as needed, the tank's lifetime will usually expand from years to decades.

The Different Types of Anode Rods

The type of anode rod chosen for a water heater depends on water quality. Magnesium rods are intended for soft water or not-so-hard water applications. As it corrodes, magnesium will dissolve into the water, making a healthy water for drinking. Aluminum rods are used for hard water or even salt water applications. Aluminum rods mixed with zinc will help remove sulfur dioxide smells (rotten eggs) from water, which will be present when there is heavy amounts of Iron in the water.