How to Set Up a Refugium for an Aquarium

A refugium is an isolated compartment inside or outside of an aquarium, which shares the same water flow and conditions as the main tank. These compartments can serve as a sump to help clean water, allow you to keep delicate species away from aggressive animals and culture food species. Refugiums can also be used as hospital tanks for injured fish and coral but should not be used for sick fish, since the shared water can spread disease. Setting up your own above-tank refugium is relatively simple.

Things You'll Need

  • Ruler or measuring tape
  • Plastic tub
  • Permanent marker
  • Fluorescent aquarium light (such as LOA model 6065)
  • Craft knife
  • Electric drill
  • Hole saw
  • 2 aquarium bulkheads
  • Brass barb fitting
  • Aquarium tubing
  • Adjustable mini-flow aquarium pump
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Instructions

  1. Lid

    • 1

      Measure the lid of the plastic tub. Find and mark the center of the lid with a permanent marker.

    • 2

      Measure the aquarium light. Mark a rectangle on the lid slightly smaller than the light.

    • 3

      Use a craft knife to cut along the lines of the rectangle. Remove the piece of plastic. The aquarium light should fit flush over the opening.

    Bulkhead

    • 4

      Use an electric drill fitted with a hole saw appropriate to your aquarium bulkhead to create a hole in the back of the tub, about 1 inch from the tip lip of the tub. Drill slowly to avoid melting the plastic.

    • 5

      Place the bulkhead. Fit the bulkhead into the hole, making certain to place the washer between the tub walls and the front of the bulkhead. If the washer is improperly located, the bulkhead will leak.

    • 6

      Attach a length of aquarium hose to the bulkhead. Place the other end of the hose into the display tank.

    • 7

      Tighten the bulkhead and test the seal. Fill the tub with water up to the level of the bulkhead to determine whether the seal is water tight.

    Water Feed

    • 8

      Drill a hole in the lid of the tub appropriate to the size of the second bulkhead. Locate the hole on the opposite end from the bulkhead. Drill at low speeds to prevent the plastic from heating up and melting.

    • 9

      Screw a barb fitting into the bulkhead. Make sure that the threads line up and that the barb fitting attaches securely.

    • 10

      Slide one end of an appropriately sized piece of tubing over the end of the barb fitting. Attach the other end to an aquarium pump, and place it in the display tank. Water should run freely from the display tank to the refugium, and back through the other piece of tubing.