Anode to suit Suburban Hot Water Service Magnesium AZ31 325mm x 17mm Slightly acidic water is fine to drink and wash with, but it can degenerate your water heater over time. Some water heaters have an in-built anode rod of soft metal that will break down instead of the other components of the water heater. Anodes should be replaced when they have degraded more than 75%, usually yearly, but this is dependent on the quality of water used. FEATURES: • Magnesium AZ31• To suit Suburban hot water systems SPECIFICATIONS: • Size: 17mm x 235mm