How to Make a Gravel Filter

Installing an under-gravel filter in your aquarium is considered one of the best natural ways to filter the water in your aquarium. The water is drawn down through the gravel of the tank, through a mesh screen, and then up through a tube to a charcoal filter at the top of the tube. This provides very good filtration for your aquarium while at the same time reducing the amount of electricity your aquarium uses. In addition, you can build the filter easily and inexpensively with components available from your aquarium pet supplier.

Things You'll Need

  • 1-inch hard plastic tubing the length of the depth of your aquarium
  • Under-gravel screen
  • Gravel
  • Water
  • Air line T-connector
  • Flexible aquarium air line
  • Charcoal filters
  • Air stone
  • Air pump
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Instructions

    • 1

      Install the tube mounts onto the plastic tubes by sliding them over the ends of the tubes. They will fit, but they are very tight. These mounts will be included with the plastic grate that covers the bottom of the tank.

    • 2

      Remove the two round plastic blanks from the base of the grate. These holes will be located at the back of the tank, and the tube mounts click into place in these holes.

    • 3

      Install the tubes into the holes in the grate, and then place the assembly in the bottom of the aquarium.

    • 4

      Cover the grate with aquarium gravel to a depth of at least 1 inch, and then fill the aquarium with water.

    • 5

      Slide the air line over the bubbler's inlet tube, and then run the bubbler down the plastic tube until it is hidden under the gravel. Install another bubbler into the other plastic tube.

    • 6

      Connect these tubes with a T-shaped air line fitting, then run another tube from the air line fitting to the air pump.

    • 7

      Install the carbon filters onto the top of the plastic tubes in the aquarium. These look like domes that slide over the top of the tubes. The bubbles force water up and out through the carbon filter, effectively neutralizing ammonia in the tank.

    • 8

      Plug the air filter into a wall socket to begin the filtering process.