I have found that the more Iodine I take, the more magnesium I need. Iodine appears to be part of calcium regulation in the body, and magnesium is a natural balance for calcium.
Different forms of magnesium have more or less effect on the bowel while being calming to the nervous system. Magnesium citrate brings more moisture to the colon and can thereby help regulate bowel movements. You may have a level of magnesium that you learn helps you feel the best.
You can take more magnesium than your colon can tolerate and end up with diarrhea. However, the blood level of magnesium in your red blood cells (RBC magnesium) can be low even while you cannot tolerate more magnesium running through your colon.
I encourage you to test several sorts of magnesium to find your optimal daily dose. I mix magnesium citrate, magnesium malate, and magnesium bicarbonate to maximize my intake. There are others, such as magnesium chloride and magnesium taurate.
You may find that the dose of Iodine you take determines how much bromine is released. If you have not taken more than 100 mg Iodoral or 130 mg SSKI , you may have more detox to go. For instance, I live near a heavily traveled freeway and will never be done with detox, because I am constantly exposed. My minimum dose needs to be 300 mg.