Oh ya, that ^ too. :lol:

What is the difference between hexahydrate and dihydrate?

4 water molecules. :D It's how much water is contained within the compound.

Ok so if you need 5 cups of hexahydrate how many cups of dihydrate would be needed?

Deitmar, why are you using the recipe #1 Part 3B measurements ?
I use the Part 3A dosing with 5 cups and 3 cups

An Improved Do-it-Yourself Two-Part
Calcium and Alkalinity Supplement System

I don't know Greg, I have been using that for a long time. Whats wrong with that recipe?

ok, I looked up #1 3B
Thats not what I am using, that one is all epsom salts. (mag sulphate)
I use 7.25 cups mag chloride to .75 cups mag sulphate to one US gal.

Nothing wrong with it that I know of. Just curious. Seems like such a small amount of sulphate to chloride.

I just looked at your link and see that it's his first/original recipe.

I see the error in my ways.
Mark in post #3 posted Randy's second, revised version of DIY supplements which advocates 5:3 as Mindy is suggesting. Mag chloride:mag sulphate
The next batch of Magnesium I mix up will be that ratio.

I just bought some J&L shlobster magnesium chloride and on the back that is the recipe given to mix your magnesium.