Seachem 323 Reef Salt 160 Gal For Natural Reef EnvironementReef Salt is a chemically sound blend of salts designed to replicate natural reef waters. It is specifically formulated for the reef environment and will provide ideal seawater concentrations of magnesium, calcium, and strontium with proper alkalinity and pH for closed reef aquarium systems. It contains all essential major, minor, and trace components found in natural reef waters, but contains no toxic or non essential components such as nitrate,