How to Set Up an Undergravel Filter in a Hex Tank

A hex tank has a smaller bottom area than many other sized aquariums, making the surface area for an undergravel filter smaller than with a standard rectangular tank. A hex tank requires an undergravel filter that is specifically designed to fit on the bottom of a hexagonal tank. It should also fit the gallon size of the tank. A 1-gallon hexagonal filter will not be large enough for a 10-gallon tank.

Things You'll Need

  • Hexagonal undergravel filter
  • Filter cartridge
  • Gravel
  • Aerator
  • Aerator tubing
  • Aeration stone
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Instructions

    • 1

      Clean the tank thoroughly and without using any chemicals that could harm the fish. If you use any type of soap or cleaning fluid, rinse the tank thoroughly at least three times to remove all traces of the cleaner.

    • 2

      Rinse off the undergravel filter before using it, even if the filter has just been taken out of the box. There may be loose cardboard particles attached to it from the retail box that could get into the water and clog the filter.

    • 3

      Insert the carbon cartridge into the bottom of the filter, if the filter comes with this cartridge. Some undergravel filters use a carbon bag, others use a foam filter or simply rely on the openings in the top of the filter to trap debris.

    • 4

      Place the aeration tube into the proper opening in the undergravel filter. Some filters will have two of these, depending on the size of the tank. The tube will fit into the large, round opening on one side of the filter. This is the tube in which the air pump tubing and the aeration stone that fits onto that tubing will go.

    • 5

      Cover the filter with gravel. Make sure that the gravel you use is not small enough to clog the openings of the filter. Most gravel that is marketed for aquariums will be the correct size.

    • 6

      Hook up the air pump with the tubing that will deliver the aeration into the water. Attach an air stone or other aeration system to the end of the tubing. Drop that end of the tubing into the larger tube that was connected to the undergravel filter.