DIY Sump Filtration

Sumps are containers of water separated from a display aquarium but hooked into the aquarium's water system. Sumps are an excellent place for filtration devices, and they provide increased water volume, which helps stabilize water parameters. When determining the size of the sump, larger is better, although even a small one will help improve overall water quality. Aim to improve biological, mechanical and chemical filtration in the sump by properly designing the system.

Things You'll Need

  • Mechanical filter media
  • Bio balls
  • Deep sand bed
  • Granular activated carbon
  • Return pump
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Instructions

    • 1

      Plan your sump design to include areas specifically for mechanical, biological and chemical filtration. Generally, mechanical filtration should come first to remove any large debris from the water. After this should come the biological filtration, followed by the chemical filtration.

    • 2

      Add your mechanical filtration media where the water enters the sump. The most common mechanical filtration media are sponges, nylon mesh and fabric-covered filters. Make sure all the water flows through the filtration media. For saltwater aquariums, another excellent mechanical filter is a protein skimmer. These devices mix air and water to remove dissolved organic compounds from the salt water.

    • 3

      Add your biological filtration. For freshwater aquariums, a common biological filter is "bio balls." These are plastic or ceramic balls or cylinders that encourage the growth of beneficial bacteria. The water should trickle over the balls so that they can absorb oxygen from the air. The bacteria that grow on the bio balls help convert ammonia to nitrate. Nitrate is far less toxic to fish than ammonia.

      For saltwater aquariums, you usually want to use a deep sand bed instead of bio balls. Deep sand beds are simply 5 inches of aragonite sand where the water passes slowly over it. Deep sand beds provide an anoxic environment (low oxygen), and the bacteria that thrive there help reduce nitrates from the aquarium water.

    • 4

      Add your chemical filtration media. The most common chemical filtration for aquariums is granular activated carbon (GAC), which can be found at most aquarium stores. You want the water to pass slowly through the GAC so it has time to absorb dissolved chemicals in the water. Other chemical filtration options include nitrate and phosphate sponges or granules. These help remove nitrates and phosphates specifically and will help reduce the appearance of nuisance algae.

    • 5

      Set the flow rate through the sump to be four times the aquarium volume per hour. This means if you have a 50-gallon aquarium, you should have 200 gallons-per-hour (gph) flowing through the sump. This gives the filtration media time work. Usually the flow rate will be set by the size of your return pump (the pump that sends the water from the sump to the aquarium).