Reef•Basis Sustain Iodine is a unique, multicomponent iodine release system, designed to nourish organisms that require iodine. It is particularly useful for soft corals of all kinds, particularly xenia, as well as gorgonians, hard corals, tunicates, marine worms such as feather dusters, sponges, macroalgae, and crustaceans, particularly shrimp. Growth rates in xenia and gorgonians will likely improve with it's use. It helps all corals and clams retain their coloration and shield against strong lighting.