Halimeda, Halimeda sp. thrives much in the same way as the beautiful Corraline Algae. It incorporates a hard calcium carbonate skeleton within its living tissue. Because of this hard coating, Halimeda has a natural protection from predation. Halimeda grows in many parts of the world including the infamous Great Barrier Reef and in the waters surrounding the Hawaiian Islands (from where it is harvested for PETSOLUTIONS.) Also known as Money Plant, Halimeda is made of a number of bladed sections that connect end-to-end to form a continuous strand. This low-maintenance plant does not require the pruning maintenance of other Marine Plants and does better when left to grow. It is tolerant of a variety of lighting and water conditions, but does not typically thrive if higher nitrates or phosphates are present. As a calcareous plant, it does grow relatively slowly in comparison to Caulerpa-family plants. Requiring excellent calcium levels for good growth, Halimeda makes an excellent decorative home aquarium addition.
Sounds like it may use up some calcium in your tank.