If you need to make a large correction, it takes a ton because the corrections are large.
How are you maintaining calcium and alk? That method can help determine the best way to dose magnesium.
You may find this useful:
OK, this thread has been many years in the making, and I'm posting it here since folks in the chem forum are probably already tired of all the threads relating to problematic magnesium testing. I'm going to propose a method, let's call it the Randy Magnesium Method, or RMM for short. All good...
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