How do I Change the Magnetic Impeller Assembly on a Marineland 250H Filter?

The Marineland HOT Magnum 250 is a Hang-On-Tank -- H.O.T. -- filter designed to process 250 gallons per hour when assembled with clean filter media. Water is pushed through the filter by a magnetically spun impeller. Small particles can become lodged in the impeller, despite the protective shroud. Lodged particles may restrict the spin of the impeller, damage the impeller blades or scar the metal spindle creating corrosion. Replacing the impeller assembly requires a tear down of the assembled canister. Periodic maintenance should include impeller cleaning to prevent particle wear and algae and bacterial build-up.

Things You'll Need

  • Paper towels
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Instructions

    • 1

      Shut down the canister. Either press the on/off switch or remove the plug from the electrical socket.

    • 2

      Remove the canister from the aquarium. Slightly tilt the canister away from the intake and outlet tubes to ensure the water does not drain onto the floor during transport. You may also turn the tubes upright to keep water from draining.

    • 3

      Lift the latch on the top of the canister filter to release the metal retaining bar.

    • 4

      Remove the canister filter lid and tubing assembly. Set the lid and assembly aside.

    • 5

      Remove the internal cartridge, filter and media.

    • 6

      Reach into the canister filter and retrieve the impeller module. Remove the module from the canister. The module is located under the flat plate at the bottom of the canister. It will look like a large black sphere with the impeller magnet sticking out the bottom. When pulling upward on the impeller assembly, the magnet may pull against the motor until the assembly is far enough away from the magnetic field to not be affected.

    • 7

      Squeeze the sides of the impeller assembly module to open the casing. Remove the impeller assembly. The impeller assembly will have a cylindrical magnet, a metal shaft, a metal spindle and two rubber boots on the spindle.

    • 8

      Inspect for damage. If the impeller assembly is dirty but not damaged, it can be cleaned with water and paper towels and replaced. Otherwise, replace the impeller assembly.

    • 9

      Insert the new or cleaned impeller assembly into the two halves of the assembly module. Press the two halves together.

    • 10

      Replace the impeller assembly module in the bottom of the canister. Reassemble the canister and attach the canister to the aquarium.