Magnesium and Potassium supplements

I have read that our cocktails can deplete magnesium and Potassium among other things.  Does anyone specifically supplement with these?  What kind?  Source?  Thanks.
Aunt Jo

Blood Clots are Common with Brain Tumors

When Chance was recently diagnosed with a blood clot in his upper left leg, he was told to go off all meds and supplements until he could meet with the hematologist. He did so and at the hematology appointment, the doctor told us blood clots are common in brain tumor patients.

We wondered why we hadn't been warned.

In Natural Strategies for Cancer Patients by Russell L. Blaylock, M.D., page 33 states: "Maintaining adequate magnesium levels is especially important in preventing surgical and postsurgical complications. Magnesium is one of those nutrients that seem to have an unlimited list of benefits. In addition to playing a role in more than 300 enzymes, it regulates blood flow, protects brain cells, protects the heart muscle, reduces the risk of cardiac arrhythmia, improves lung function, improves kidney function, and prevents one of the most frightening complications of major surgery: blood clots.

I have used magnesium in my neurosurgical patients for more than fifteen years and have never had a patient develop postoperative blood clots in the legs or lungs."

Of course, magnesium is a blood thinner too, so how much to take could be problematic...

Stephen, any thoughts?