Iodine is present in natural sea water in a very low concentration (0.6 mg/L or 0.06 PPM) and this iodine occurs as several different forms including iodide, iodate, molecular iodine and hypoiodite.

It is a vital element for normal developments of marine macroalgae, corals, sponges and tunicates. Reef aquariums that are depleted of iodine may have poor results on maintaining specific kinds of organisms.

Iodine also helps protect and remedy the problem of corals and clams bleaching. This is because iodine is needed by corals to build UV protective pigments and is also capable of detoxifying radical oxygen that is produced from over photosynthesis.

Great results can be seen with soft corals like Xenias, mushrooms, leather corals.