Highly-concentrated, extended activity iodide solution, Provides iodide, which is important to hermatypic corals and other invertebrates harboring zooxanthellae, macroalgae, and also to the health of fishes, Stronger than most competing products, The nature of iodide sources used makes Iodion more effective than standard iodide-solutions, Suitable for use by aquarium hobbyists of all skill and experience levels, Composed of purified water and ultra-high purity materials, Formulated by a marine scientist, Liquid, 500-ml, SKU: RYLHC1036