Magnesium chloride hexahydrate or magnesium chloride for magnesium dosing.

[JordanM]

Is there a difference between using these two when dosing magnesium? They seem to be used interchangeably with one another and does using one or the other change the amount you dose when using the calculators?

 

[Cory]

Yes theres a difference. Hexahydrate has more water so youll need more to weight to raise magnesium than anahydrous form iirc.

 

[JordanM]

I used Magnessium Chloride Anhydrous 99%. When I diluted this in RODI there is a little grey/black precipitate in the bottom. I assume this is the magnesium that did not go into solution?

 

[Cory]

Im not sure what it is but heres a calculator you can use:

http://reef.diesyst.com/chemcalc/chemcalc.html