Carbonate has more calcium per pill, but needs an acid environment to be absorbed, so not likely the best formulation if you are taking antacids or do not take them with food.
Icarbonate inecalcium eninzi kwipilisi nganye kodwa ifuna iasidi eyaneleyo ukuze ifunxeke, ngoko ke ayifanelekanga ukusetyenziswa xa usebenzisa izinto ezilwa neasidi okanye ungazityi ngaxeshanye nokutya.