I am experimenting with taking two different types of both calcium and magnesium hoping that I can get better absorption that way. I take calcium carbonate and magnesium oxide together in one liqui-cap, then take calcium citrate with Vitamin D, and magnesium malate. This may be overkill, but I want to get the best I can for joint health. My Naturopath told me that ionic and colloidal minerals might be easier absorbed, but they are in such small concentrations in most commercial liquid mineral formulas that it is not cost effective to use them. The best ionic minerals are in leafy green vegetables, but often its hard to know how good those are. Even a lot of organic veggies look old and tired in the stores. I also use a green drink for minerals and anti-oxidants. Adding those have really helped me become more alkaline without taking a lot of weird stuff.