How to Set Up a Refugium

A refugium provides refuge for your aquarium life that needs to be protected from more aggressive species. A refugium is connected to the main display tank, but it is a separate space, and species cannot travel between the two tanks. Both tanks filter the same water. Some people confuse refugiums with reverse photosynthesis arrangements, which are usually installed beneath the display tank. Many people keep sea horses, types of shrimp and other small fish, which will not fend for themselves in a community tank, in their refugiums.

Things You'll Need

  • Main display tank (can be any size)
  • Smaller tank for refugium (such as 10 or 30 gallon)
  • Fish for refugium
  • Light
  • Plant life such as macroalgae and mangroves
  • Sump (optional)
  • Water
  • Sand
  • Protein skimmer or powerhead
  • Tubing
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Instructions

    • 1

      Put sand in the bottom of the tank you are using for the refugium. For example, if you are using a 10-gallon tank, then you want a sand bed of about 4 to 6 inches. It is best to use live sand or marine mud product.

    • 2

      Place the refugium tank next to the main display tank. The water levels should be about equal. If you use a sump, then position the sump so that the refugium drains into it. If your system is sump-free, then you can mount the refugium so it is above the display tank. Let gravity do some work for you so that you do not need to purchase an additional pump.

    • 3

      Supply the refugium with water. The water should come from below the main tank's water surface. The refugium's water should not be overflow from the main tank because the surface water is full of oils, which you do not want in your refugium. The best way to get water into the refugium is by tapping off the return line of your protein skimmer. You can also put a powerhead under the water's surface of the main tank and tubing leading into the refugium. The water in the refugium should not be stagnant, but the flow should not be so hard that it disrupts the sand in the bottom.

    • 4

      Place a light over the refugium. This light does not have to run on the same time system as the light over the main aquarium. Some people run the two lights at opposite times to try to stabilize the pH in the system. Because several different types of lights exist for aquariums, choose a light that works best for your fish species and plants. Some research or a discussion at the store where you purchase your fish will help you determine the best lighting for your situation.

    • 5

      Add some marine plants to the refugium. Mangroves are popular plants to put in a refugium. They help reduce nitrate. You also should put in some macroalgae, which is more commonly known as seaweed. Some people add certain invertebrates that will not eat the plants they are trying to grow in the refugium. Once the refugium is set up and stable, you are ready to house fish in it. If you are not sure which types of plants are best for your fish, then talk to an expert at your local aquarium store for recommendations.