Using magnesium chloride orally can cause problems with loose stools. In fact this is the single most limiting factor to oral use of magnesium.
You might try to back off the oral dose and use magnesium chloride only transdermally in skin application, foot baths or full baths and see if this helps. We have not heard of sodium bicarbgonate causing this, and not knowing your dosing it is hard to say.
You might cut back on your doses for a few days to see if it makes a difference.
Claudia French RN, LPHA
Assistant Director, IMVA