Reef Salt™ is a chemically sound blend of salts designed to replicate natural reef waters. It is ideal for both reef aquaria and fish only aquaria. It is specifically formulated to maintain ideal and stable seawater concentrations of magnesium, calcium, and strontium with adequate alkalinity and pH for closed aquarium systems. It contains all essential major, minor, and trace components found in natural reef waters, but contains no detectable quantities of toxic or non-essential components such as nitrate, phosphate, silicate, arsenic, cadmium, or beryllium. Biological components, such as vitamins and amino acids, are unstable in concentrated salt. Since they are depleted from the aquarium more rapidly than they can be replenished by routine water changes, these components are best supplied by regular addition of Seachem's Reef Plus™. Reef Salt™ mixes with excellent clarity to a pH of 8.2-8.4, an alkalinity of 4 meq/L and calcium of 400-420 mg/L, depending on specific gravity. Aquarium Use Only! Keep Away from Children!