Purpose of a Refugium in a Reef Tank

Refugiums, also know as sump pump boxes, are secondary tanks that sit outside the main fish tank. Although they are separate containers, they are generally set up to share a water supply with the main tank. They are commonly seen in large reef tanks, which are saltwater set ups that emulate a reef environment, including fish, anemones and coral.

  1. The Facts

    • Refugiums are always smaller than the main aquarium, but may be set up as complete environments of their own, with substrates, corals, plants and sea creatures. They are generally placed behind or below the reef tank.

    Setup

    • Refugiums are connected to the reef tank by at least 2 plastic tubes, which are responsible for the circulation of water between the two tanks. A refugium also incorporates the pump and filter system, which provides the muscle behind the water circulation.

    Refuge

    • As their name implies, refugiums act as a refuge for creatures that can't survive in the main tank. Baby fish that need to grow to be safe with larger fish, naturally smaller creatures and any creature that might become prey in the larger tank can be kept safe in a refugium.

    Storage

    • Refugiums almost always act as a host for the pump and filter equipment, and are sometimes set up specifically for that purpose. Putting the hoses, wires, pump and filter in the refugium, and then placing it behind the main tank, effectively "hides" all of this equipment.

    Food Growth

    • Plankton, krill, small fish and algae can all be safely raised in the controlled environment of a refugium, and fed to the creatures in the main tank under supervision, as needed. Plants can also grow in refugiums, adding nutrition and oxygen to the water without cluttering up the main tank.

    Considerations

    • Because refugiums can house both small creatures and the pump and filter system, monitor the suction to make sure that small fish aren't getting sucked into the pump. It's also important to make sure that the water pH and coral are safe for all the creatures in the circulated water.