Magnesium chloride
The salt used to supplement magnesium in reef aquariums. Component of the third solution of the Balling method.
Detailed explanation
Magnesium chloride hexahydrate (MgCl2 6H2O) dissolves easily in osmosis water. Standard concentration: 50-60 g per litre.
Magnesium sulfate (Epsom salt) also raises magnesium but adds sulfates. Magnesium chloride is preferable in marine aquariums.