Figure 3 Curve obtained in E.D.T.A. 10 g/1 solution at the sixth cycle.

The results of experiments are reported in Table 1 for E.D.T.A. and in Table 2 for N.T.A. both being 10 g/1 concentrated solutions.

It is seen , during the different cycles, that the term CA is decreasing because easily accessible calcium is already sequestrated. Moreover, if we compare the chelating agents, the action of E.D.T.A. is faster than the action of N.T.A. is.