How to Build a Salt Water Aquarium Refugium

Reef tanks especially benefit from refugiums.

A saltwater refugium is an "appendage" tank that shares water with an aquarium. Regiums help remove dangerous nitrates caused by decaying organic matter. They provide a safe zone for macroalgae or zooplankton or macroalgae. Refugiums can even be used to propagate corals, house small fish, shrimp, or fry that would get eaten in the main tank. Refugiums add water volume to an aquarium, which helps stabilize water temperature and pH, and aids in oxygenation.

Things You'll Need

• 10 to 40-gallon acrylic fish tank
• Acrylic cutter
• Pvc piping
• Silicone sealant
• 2 Submersible pumps
• Plastic egg crate
• Live sand

Instructions

1. Cut holes in which will fit your PVC piping on each of the two smaller acrylic panels of your refugium tank. Position the hole for inflow closest to your main tank and a few inches higher than the outflow hole.

2. Place an aquarium-safe submersible pump which is sized appropriately for your aquarium's water volume in your main aquarium, or your sump tank if you have one.

3. Attach PVC piping leading from the submersible pump in your aquarium or sump into the inflow hole of your refugium. Seal the PVC into place with silicone sealant to render it watertight.

4. Place an appropriately sized submersible pump in your refugium.

5. Attach PVC piping leading from the submersible pump in your refugium into your aquarium or sump tank. Seal the PVC into place with silicone sealant to render it watertight.

6. Place a base of clean plastic egg crate two to four inches above the floor of the refugium, creating a gap called a plenum. Julian Sprung's "Jaubert's Method, the Monaco System, Defined and Refined" explains how a plenum breaks down organic waste and oxygenates water in the refugium.

7. Add two to four inches of live sand, which is sand especially prepared to add beneficial bacteria to an aquarium.

Tips & Warnings

• Adding some live rock to your refugium helps naturally filter water and provide hiding spots for copepods and macroalgae. Live rock is specially prepared rock that houses beneficial bacteria.

• Provide a tight-fitting lid to your refugium to prevent splashing and to keep small creatures from escaping.

References

• Advanced Aquarist's Online Magazine: Jaubert's Method, the "Monaco System," Defined and Refined