if you want cal/mag then i would suggest 100% pure coral calcium which naturally has a 2:1 calcium/mag ratio in it, exactly what the body needs. it also has the full spectrum of trace minerals. the other stuff is usually made from crushed rock and can form deposit in your body that aren't healthy. but make sure it says 100% pure, or you will get some with fillers and rice crap in it. why they feel the need to pollute a perfect substance like that i do not know.