Macroalgae such as Halimeda, Caulerpa, and other large celled algae are valuable additions to a saltwater aquarium. Algae and all photosynthetic creatures serve two important roles in the ecosystem of the oceans and aquariums. Light provides the energy for plants (and zooxanthellae) to convert carbon dioxide into oxygen and sugars, making it a great food source for tangs, angels, and other herbaceous animals. macroalgae reduce the available levels of phosphates and nitrites/nitrates, an excellent form of natural filtration.
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