Why A Refugium

A refugium is defined as a stable place where endangered species can live even when the surrounding environments are changing. For the Aquarist, refugium means a refuge that shares the same water as the display aquarium but is isolated from the rest of the aquarium.

A well-designed refugium provides many advantages for your main aquarium. The macro algae and sand that is in your refugium will become natural filters for your display aquarium by reducing phosphates and nitrates. By reducing these contaminants from your aquarium, you will help eliminate the growth of unwanted algae in your tank.

The other advantage to having a refugium is that the lighting you put in will be on the opposite cycle as the light in your main aquarium, this will help stabilize the oxygen and pH levels in your aquarium.

The display light will be on during the day and off at night. When the light goes out carbon dioxide (CO2) levels will rise because photosynthesis is no longer occurring. CO2 is an acid and will lower the pH in your aquarium. With the refugium light on at night, the plants you have in your refugium will use the CO2, make oxygen and stabilize the pH.

Another benefit for having a refugium is that since it is a little environment separate from your display aquarium you can put in it small crustaceans such as copepods and amphipod. These can be netted to supply a food source for your fish or they can migrate naturally to the display tank via the connection lines. For this reason predator fish should not be placed in a refugium or they will eat your entire food source.

Refugium Types

There are many different types of refugiums to choose from. You can choose from those that hang from the side into the tank, stand-alone, built-in or even internal refugium.

What To Put In A Refugium

Besides sand, micro algae and crustaceans, you will also want to put in your refugium aquatic life that will not do well in the company of more aggressive fish. Many Aquarists will put in such aquatic life as seahorses, some shrimp and small fish.

Conclusion

Having a refugium as part of your display aquarium provides many benefits for you and your fish. It keeps oxygen and pH levels stable and reduces the amount of algae in your aquarium. A refugium makes the work involved in keeping a saltwater or reef aquarium easier.