Reef Iodide, 4 L / 1 fl. gal. Raises iodide and contains no toxic iodine A concentrated stabilized potassium iodide source for reef aquaria that will restore and maintain iodide levels found in natural seawater Formulated to provide a safe source of iodide that will not convert to toxic feric iodine under storage or reef conditions Iodide is an important element required by invertebrates and many soft corals 250 milliliters treats 5000 US gallons