Sacrificial Anodes protect against corrosion that occurs as the result of electrolytic action. Anodes have been used for many years in a variety of applications.
Hot Water Storage Tanks
Other Steel Structures Immersed in Water
Many of the large domestic water storage tanks today have cement coatings, nearly eliminating the problem of internal rust. Some areas of the tank cannot be protected by the lining due to the necessity of water flow i.e. couplings, inlets, outlets, etc. Therefore many tank manufacturers initially supply anode protection provided by the insertion of special tank anodes.
These anodes should be replaced on a scheduled basis. Depending on the water conditions anodes will deplete at various rates, typically every 2-5 years. Your HydraStone specialist will determine the rate of depletion and recommend future anodes changes.
Not sure if your tank has anodes?