My water heater has 2 magnesium anodes, should I replace both?

The answer is no and that is why Corro-Protec offers different models adapted to tank sizes.

If your water heater has two anodes, you can replace one of them with our Corro-Protec imposed current anode and leave the other one in place. Even if you install the Corro-Protec anode to eliminate the rotten egg smell in your hot water, you don’t need to remove the second magnesium anode.


  1. Avatar Thor Collard on April 14, 2020 at 9:24 am

    Why is this the case? Don’t the bacteria still interact with the magnesium? Is this also the case if you have a water softener and two anodes?

    • Avatar Corro-Protec on April 14, 2020 at 9:55 am

      Hello Thor,

      If the smell came from the reaction between the magnesium rod and your water, our Corro-Protec anode will create a protection around the second magnesium anode rod that will stop this reaction.
      If the smell came from the bacteria, our Corro-Protec create an environment where the bacteria is not able to survive. Having a magnesium rod or not won’t make any difference.

      Hope this helps,

  2. Avatar ken on April 24, 2021 at 4:01 pm

    What about an aluminum rod? My water heater has two aluminum rods, can I leave one in and install the powered rod in the other spot?

    • Avatar Corro-Protec on May 5, 2021 at 7:05 am

      Yes, the Corro-Protec can be installed with a magnesium, aluminium or zinc anode rod without any problem.

  3. Avatar William Pherson on May 25, 2021 at 8:22 am

    I have a brand new Ruud 80 gallon electric water heater with two anodes and also brand new Kinetico water softener. Put the water heater in three weeks ago and all of a sudden nasty rotten egg odor in hot water. Since I have dual anodes:

    1) Do I use the Corro ProTec rod still for the 80 gallon size?
    2) Does it matter which anode rode I replace?

    From what I’ve read here I only have to replace one of the original anode rods and leave the other.

    Thank you.

    • Avatar Corro-Protec on May 25, 2021 at 8:25 am

      Hello William,

      1. Yes you need to buy the Corro-Protec 40 to 89 gallon to protect this tank.
      2. No, just replace the one that’s easiest to replace.


  4. Avatar DAVID KEMP on October 21, 2021 at 9:02 am

    I have spitting hot water from excessive hydrogen production from the two magnesium anodes in my 60 gallon gas water heater. Can I still just replace one anode? One of them is easily accessible, the other is under the power exhaust. Thanks for the help!

    • Avatar Corro-Protec on October 21, 2021 at 4:01 pm

      David, replacing one magnesium anode rod with the Corro-Protec powered anode will solve that problem. You can let the other anode in place and it will not affect the performance of the Corro-Protec.

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