Supplement containing concentrated iodine. In marine aquariums, iodine is crucial for the general functioning of cells and the transfer of nutrients between them. The iodine is constantly consumed by the inhabitants of the reservoir, therefore, without supplementation, its level decreases quickly. Iodine is used by corals to synthesize pigments that allow them to adapt to variable lighting conditions and protect the fragile coral tissues from UV rays. Iodum intensifies the dark and purple blue coloring of hard corals. An appropriate iodine content in the seawater tank promotes shrimp moult. A regular iodine dosage keeps iodine content at the same level as in natural seawater.