How to Use Marbles for an Underground Filter Substrate

When using an underground filter system in an aquarium, choosing the substrate that goes on top is crucial to the proper function of the filter. Marbles, also known as marble chips, are one beneficial aquarium substrate for this set-up. The calcium carbonate-based material will serve as a pH buffer while also providing enough surface area for beneficial bacteria to grow. Using marble chips for an underground filter substrate is fairly easy and can be installed in an empty aquarium.

Things You'll Need

  • Marble substrate
  • Colander
  • Empty aquarium
  • Underground filter system
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Instructions

    • 1

      Select a marble chip that is about .15 to .2 inches in diameter. This material can be purchased from a fish store.

    • 2

      Place the marble chips in a colander and run them under clean, flowing water. Move the chips around in the container to ensure that they are thoroughly cleaned and that all dust, dirt and debris is washed away.

    • 3

      Insert an underground filter plate system into the bottom of an empty aquarium. Each filter plate system is installed differently, so follow your brand's directions. Ensure the system's riser tubes are properly secured to the filter plate as directed to prevent marble chips from sliding underneath the plate through the exhaust holes.

    • 4

      Layer 2 to 3 inches of marble chips on top of the filter plate. Arrange this material in a slope, moving from the back of the aquarium to the front. This design will force larger debris to roll to the front of the aquarium, making it easier to remove.

    • 5

      Add any decorations on top of the marble substrate, such as rocks, drift wood and plastic figures. Ensure all additions to the aquarium have been washed and are free from chemicals. Fill the aquarium with de-chlorinated water.