It is the magnesium in seawater that allows it to hold high levels of calcium and carbonates in solution without precipitation. Magnesium Sulphate is an economical source of magnesium that can be used on its own, or mixed with Magnesium Chloride to create an ionically balanced magnesium additive if required.
5 grams of Magnesium Sulphate heptahydrate per 100 litres of aquarium water will raise magnesium levels by around 5ppm. Simply dilute in fresh water and add slowly to an area of high flow.
Suitable for use as part of the 'Balling Method' of aquarium supplementation, first developed by Hans-Wermer Balling in Germany.