Marine Aquarium Refugium – What and Why….

A refugium is essentially part of a sump, where one purposely grows algae! Macro algae species, such as caulerpa or chaetomorpha are grown in the refugium because they will absorb dissolved nitrates and phosphates from the water and store it internally at a much higher concentration than the natural seawater around them. They effectively remove these harmful substances which in turn keeps the fish and invertebrates healthier. It also helps reduce the growth of algae in the display aquarium since nitrates and phosphates are eaten by the macro algae before the detrimental algae in the display tank has the opportunity to feed upon them.

A refugium is essentially part of a sump, where one purposely grows algae! Macro algae species, such as caulerpa or chaetomorpha are grown in the refugium because they will absorb dissolved nitrates and phosphates from the water and store it internally at a much higher concentration than the natural seawater around them. They effectively remove these harmful substances which in turn keeps the fish and invertebrates healthier. It also helps reduce the growth of algae in the display aquarium since nitrates and phosphates are eaten by the macro algae before the detrimental algae in the display tank has the opportunity to feed upon them.

In addition a refugium also houses invertebrates such as copepods and amphipods which are food for many reef fishes. Because there are no predators in the refugium these beneficial crustaceans will reproduce and thrive. They will make their way back up to the display aquarium through the water column where they will serve as another food source for the fish and coral.