What is a refugium?

A refugium, as defined in the aquarium hobby, is as an area or refuge where micro-organisms can live and breed without the worry of predation from fish or other organisms. Macro-algaes are also kept in refugiums to aid in waste (nitrate and phosphate) removal from the aquarium’s water. Many people setup refugiums as part of the filtration system for their saltwater aquarium, especially with reef tanks, where nutrient control is a huge concern.

Besides the roll of a micro-organism farm to help feed corals, fish and other invertebrates in your tank and a nutrient control filter, refugiums also help to stabilize the pH of your tank. During the daytime, while the lights are on over your reef tank, the different algae will photosynthesize. The algae will take in CO2 and release 02 while producing sugars to feed themselves. But during the nighttime, they will respire, meaning they take in O2 and release CO2. The CO2 produces carbonic acid which will lower the pH. By running the refugiums light on a reverse daylight period (opposite of the main tank’s light) the algae in the refugium will help balance out the CO2 and O2 production and maintain a more stable pH level.

I've written an article that answers some frequently asked questions about refugiums. You can check it out here. If you have any questions after reading this article, don't hesitate to contact us. We're happy to help!

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