What is Magnesium Chloride Technical Grade and what is it used for ?

magnesium chloride hexahydrate

magnesium chloride hexahydrate

What is Magnesium chloride hexahydrate

Magnesium chloride hexahydrate is a naturally occurring salt with the formula MgCl2 6(H2O). It is mostly produced from sea water and in particular the Dead Sea. It is a colourless to white, odourless salt with a bitter taste. It has been used for centuries as an aid to improving health and well being. Its therapeutic properties are well recognised and people flock to the Dead Sea every year to bathe in its water to rejuvenate themselves. The main uses for magnesium chloride are in the paper, textiles, cement and refrigeration industries. It also finds major applications as a de-icer and a water treatment in aquariums.

Properties of magnesium chloride hexahydrate

  • CAS No.: 7791–18–6
  • EINECS: 232–094–6
  • Magnesium chloride hexahydrate: 99% minimum
  • Magnesium chloride: 47% minimum
  • Calcium chloride: 2.2% maximum
  • Sodium chloride: 0.5% maximum
  • Potassium chloride: 0.2% maximum
  • Formula: MgCl2 6H2O
  • Purity: 99%
  • Mol weight: 203.3
  • Density: 1.569
  • Melting point: 117C
  • Water solubility: 2350 g/L (20 C)
  • Appearance:: White flakes
  • pH: 8.4 270g/l at 20C)
  • High quality magnesium chloride from the Dead Sea
  • Free from phosphate, bromides and ammonia
  • Dissolves quickly to provide clear solution

Where to Buy Magnesium chloride online


  • Additive for marine aquariums (see below for details)
  • For batheing
  • Used as a deicer and prevents the formation of ice on surfaces
  • Used in the manufacture of textiles, fire proofing agents, cements and refrigeration bri­ne.
  • Used to make sorrel cement.
  • Used for dust control.
  • For the manufacture of magnesium metal and other magnesium compounds.

Magnesium Chloride for health benefits

For many years Magnesium chloride has been used for batheing and ingesting to improve health and well being. For an insight into the many health benefits of the “Miracle mineral” click here

PLEASE NOTE that although our magnesium chloride is a natural salt produced from the waters of the Dead Sea it has not been purified to be taken orally or ingested and as such we do not promote it for this purpose.


Magnesium chloride hexahydrate is for adding magnesium to sea water. Severely low values of magnesium (900 mg/L or below) can cause low pH values and an inability to maintain proper alkalinity and calcium values. If magnesium becomes too low, coral growth will stop and followed by a decline in coral health. Carbonates and calcium are essential for all growth of corals, coralline algae, clams and invertebrates. Maintaining the correct magnesium values is very important and is indirectly responsible for coral and coralline algae growth by making it possible to maintain correct calcium, alkalinity and pH values. The magnesium content must often be increased, as shortfalls in the content can arise for various reasons. The normal magnesium content is around 1.30 – 1.40 mg/litre (1300–1400 ppm). To increase the magnesium content you need magnesium chloride hexahydrate or a mixture of magnesium chloride and magnesium sulphate (ratio of 7:1).

Visit our Reef Range & Aquarium Information site

How to dose aquarium with magnesium chloride

50g will raise Magnesium levels by approximately 60ppm in 100 litres of salt water. It is not recommended to increase Magnesium levels by more than 60ppm per day. Simply mix the required amount into a few litres of Reverse Osmosis Water, once dissolved, slowly add to your tank in an area of high flow, preferably over a period of an hour. Alternatively add to your evaporation top up water and top up as normal.

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Magnesium Chloride as a de-icer

Magnesium chloride is considered by some to the best overall ice melting compound. It is safe to use around plant life and it is less corrosive than other ice melting compounds. Magnesium chloride is a hygroscopic compound meaning it absorbs moisture. This allows the magnesium chloride to dissolve into a brine solution very quickly hence melting ice and snow very quickly. Relatively harmless to plant life, magnesium chloride is an environmentally friendly alternative for melting ice and snow. Magnesium chloride can effectively melt ice and snow in temperatures as low as –30 degrees Celsius.

Magnesium chloride is safe to use around animals and it will not affect the paws of cats or dogs etc. It does not produce any residues that can damage carpets etc.

The product is simply applied by sprinkling the powder over the ice. When used as a solution magnesium chloride has the added advantage of preventing ice forming on surfaces when applied before freezing. This solution is made up by dissolving 30g per litre of water. It can be sprayed at a rate of approx 5 sq m per litre.

Health & safety

Not a hazardous substance or mixture according to Regulation (EC) No. 1272/2008.

See MSDS for magnesium chloride hexahydrate for full details


Where to Buy Magnesium chloride online


Where Buy Magnesium Sulphate / sulfate online



About mistralhowto

formulation chemist

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