Since decreasing conductivity is only observed in pH ≥ 12, Figure confirms the observation that additive Ca 2+ ions can only preferentially adsorb on CaCO 3 precipitates in high alkaline environments. This raises even more questions on the mechanistic role of pH in the process. Interestingly, other studies show that increasing alkalinity enhances the dehydration of Ca 2+ ions in aqueous systems. The dehydration step releases Ca 2+ ions from ionic species such as CaOH + and their complexes. It is thus probable that, in high alkaline conditions, the dehydration step increases the concentration of additive Ca 2+ ions available to adsorb on the precipitates and impede their growth. Up to the solubility limit of Ca(OH) 2 (∼18 mM) in H 2 O at room temperature, the concentration of Ca 2+ ions was previously reported to vary linearly as Ca(OH) 2 solution conductivity: [Ca 2+ ] ≈ 0.4*Conductivity. Therefore, as shown in Figure (inset), the decreasing conductivity with decreasing pH confirms that the concentration of additive Ca 2+ ions similarly decreases. This, the literature suggests, is due to the hydration of the additive Ca 2+ ions. As observed in this study, it impacts their ability to selectively adsorb on the precipitates, thus limiting their growth inhibitory efficiency.