Seachem 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 aquariar it is specifically formulated to maintain ideal and stable seawater concentrations of magnesium calcium and strontium with adequate alkalinity and ph for closed aquarium systemsr it contains all essential major minor and trace components found in natural reef waters but contains no detectable quantities of toxic or non essential compone