I use the calculator from BRS
http://www.bulkreefsupply.com/i6/Calcium-and-Alkalinity-Calculator./information.html
It generally takes a good amount to raise your Mg.
You could always check the Mg levels after you're done to make sure it's correct.
Shouldn't you be mixing that mgcl with epsom salts in a 3-5 ratio to balance things out?
We use essential cookies to make this site work, and optional cookies to enhance your experience.