Macroalgae are large, photosynthetic algae grown in marine aquariums. They serve as a food source for herbivorous animals, filter impurities from the tank and add an aesthetic value to the aquarium.
Some types of macroalgae found in saltwater aquariums include halimeda, caulerpa sp. and maiden's hair. Each type of macroalgae has specific growing needs, but in general, all macroalgae do well in good water conditions and bright light. Algae filters are considered natural approaches to filtering the aquarium tank. Filters consist of one or more algae types grown in a sump or refugium below the main aquarium or in a side-refugium.