Refugiums have been a popular addition to reef aquariums for many years. There are many ways a refugium can benefit your aquarium, and multiple ways to add one.

A refugium is just what it sounds like, a refuge. The purpose of a refugium is to create a secure place for beneficial animals that can survive in your main aquarium. Depending on what life you add to a refugium, there several benefits that can come from your refugium.

Nutrient Removal

The most common reason for adding a refugium is as a form of filtration. Adding live rock and live sand to a refugium can serve as a bacterial filter for the aquarium. But the most efficient way to use a refugium as a filter is through algal-based filtration. Algae added to a refugium removes waste such as nitrate and phosphate by using these compounds as fertilizer. Sometimes algae cannot survive in the main display because fish eat it. However, it can survive in a refugium. The two most popular kinds of algae for refugiums are Chaetomorpha and Caulerpa.

Aquarists using Caulerpa will benefit from using a nutrient-enriched substrate such as Ecosystem Aquarium Miracle Mud or CaribSea Refugium Mineral Mud.

Plankton Generation

Many animals, including corals, sponges, and some fish, benefit from live plankton as a food source. These animals will eat plankton in the main display aquarium, but the plankton can proliferate in the safety of a refugium. Some of this plankton then makes its way back into the main display tank, where your animals can feed on it. To generate plankton in your refugium, you will need to have an area for the animals to proliferate. This can be live rock, mud, live sand, or a dense algal growth.

Increased Stability

Types of Refugiums

There are four different kinds of refugiums: in-tank, hang-on, all-in-one, built-in-back, and in-sump. In-tank refugiums, such as the Fiji Cube Refugiums, are placed inside an aquarium or sump. They are the most cost-effective but also the most unattractive. Some all-in-one aquariums, such as the Coralife BioCube, have a section of the back filtration compartment that can be used as a refugium. For larger aquariums and for setups that completely hide the refugium, the IceCap XL Reef Sumps, and FijiCube Advanced Reef Sumps (Size 20 & Larger) are the best choices.