Twenty six synthetic andfour natural water samples were analysed for their ionic composition and ionic strength before and after saturation with CaCO3. Their measured and calculated pH after saturation were highly correlated (r = 0.965). Twenty three water samples resulted in positive values of saturation index, leading to increase in their sodium adsorption ratio after equilibration with CaCO3. Equation proposed by Bower et a1. (1965) can be-used to calculate pHc of waters. The effect of ion complexation on SAR was negligible.
Water samples, CaCO3, pHc, sodium adsorption ratio
