Reef Iodide is a concentrated (8,000 mg/L) stabilized potassium iodide source for reef aquaria that will restore and maintain iodide levels to those found in natural sea water. It is formulated to provide a safe source of iodide that will not convert to toxic free iodine under storage or reef conditions. Iodine is as toxic as chlorine and should never be used in a reef system. However, iodide is as safe as chloride.