Na + ions can be incorporated into CaCO 3 crystal lattice. Their inclusion promotes the crystallization of irregularly shaped calcite crystals as seen in Figure . Though Na + ions have ionic radius comparable to Ca 2+ ions, they do not exhibit inhibitory effects on the growth of CaCO 3 precipitates, despite a high pH condition. This further shows that a high alkaline pH, in and of itself, does not produce the significant growth inhibition observed in this study. Rather, it is the availability of additive Ca 2+ ions in a high pH environment. The conductivity of the growth-inhibiting solution is a measure of its ionic content. Thus, conductivity changes can either be a result of the increasing concentration of precipitants counter ions (Equation ) or decreasing concentration of additive Ca 2+ ions in the suspension.