first off you should never supplement calcium, getting too much destroys bones, it doesn't help them.
second off if you use ZMA you should absolutely not even think about stacking calcium with it. it will actually block Zinc from being absorbed. this is common sense shit and no wonder so many people have low T levels.. low zinc = low T.
unlike what the food industry want you to know the body stores calcium in our bones already, .. it should be viewed as an electrolyte along with magnesium, potassium and yes salt. and no you don't supplement with it, you supplement the other 3 if you sweat out a lot