A magnesium anode is a type of sacrificial anode used in water heaters to protect the tank from corrosion. Made of magnesium, which is more reactive than the steel of the tank, the anode rod sacrifices itself by corroding in place of the tank. This process, known as cathodic protection, significantly extends the lifespan of the water heater by preventing rust and corrosion of the tank's walls. Magnesium anodes are particularly effective in areas with soft water, where the lack of minerals in the water can increase the rate of corrosion on the tank.
/mæɡˈniːziəm ˈænoʊd/
A magnesium anode is a type of sacrificial anode used in water heaters to protect the tank from corrosion. Made of magnesium, which is more reactive than the steel of the tank, the anode rod sacrifices itself by corroding in place of the tank. This process, known as cathodic protection, significantly extends the lifespan of the water heater by preventing rust and corrosion of the tank's walls. Magnesium anodes are particularly effective in areas with soft water, where the lack of minerals in the water can increase the rate of corrosion on the tank.
What does a magnesium anode do?
It sacrifices itself to corrosion so the steel tank does not rust, extending the life of the water heater.
Source: The Cooling Company
Magnesium anodes corrode first to protect the tank from rust.
A homeowner notices their water heater lasts longer than average because the magnesium anode rod is inspected and replaced regularly, protecting the tank from corrosion over time.
To ensure the continued effectiveness of your water heater, inspect the magnesium anode rod annually and replace it if more than 50% corroded. This simple maintenance task can prevent premature tank failure and avoid costly replacements.
“To ensure the continued effectiveness of your water heater, inspect the magnesium anode rod annually and replace it if more than 50% corroded. This simple maintenance task can prevent premature tank failure and avoid costly replacements.”
Magnesium anode rods can sometimes cause a sulfur or "rotten egg" smell in hot water due to reactions with certain bacteria.
How often should I replace a magnesium anode rod?
Check yearly and replace when more than half of the rod has corroded or the core wire is exposed.
Is magnesium or aluminum better for my water heater?
Magnesium offers stronger protection in soft water, while aluminum typically lasts longer in hard water.
Why does my hot water smell like sulfur?
Magnesium can react with bacteria in some water supplies and create a sulfur odor. A different anode type may help.
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