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. Marc on January 31, 2022 at 4:52 pm

    How do I know which is the anode for my heater? There are 3 caps, two of which are same size. Plastic caps and insulation on all. I don’t want to break seal on wrong one.
    Model is E1F50RD045V. With the small cap in back, which is correct of two in front? Do I have 2 anodes to replace. It’s well overdue .

    • Corro-Protec on February 3, 2022 at 8:04 am

      Looks like the anode rod is located right between the cold water inlet and the pressure relief valve.

  2. Cliff on January 11, 2022 at 9:05 am

    Is it true water softener cut the life of an anode?

    • Corro-Protec on January 12, 2022 at 7:49 am

      Cliff, yes the water softener will shorten the lifespan of the magneisum sacrificial anode rod.

  3. Carol Blair on January 4, 2022 at 5:10 pm

    If we are having to replace our anodes due to them having detoriated. We flushed the tank and removed the old anode material. Is it ok to leave one of the bad ones in and just replace the one? I didn’t know if it mattered because they are detoriated. I see where it is ok to leave if for bad smelling water but our situation is different.


    • Corro-Protec on January 5, 2022 at 8:30 am

      Hello Carol, you can let an older anode inside the tank without any problem if you are installing a Corro-Protec anode.

  4. 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!

    • 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.

  5. 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.

    • 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.


  6. 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?

    • 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.

  7. 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?

    • 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,

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