The maximum at the end of section I (Figure , denoted by the asterisk *) marks the onset of nucleation of solid precipitates. The following decrease in free calcium concentration is caused by the growth of the nuclei to bigger crystals of calcium hydroxide. The final plateau (section III) matches the solubility of the precipitated phase Ca(OH) 2 (dashed gray line in Figure ). The deviation between the measurements was checked through three repeated measurements (Figure ).