Why the conductivity of wastewater is increased after resin?

Question

Dear all,
The resin removed from the boiler water system, we would like to reuse, to pure the rainwater, for the supplies of cooling tower. In the Lab. test, we find the wastewater after resin, the conductivity is increase very much.
(1). Why the conductivity increase? We check the water qualities, the ions is removed (the resin seems work).
(2). The ions is decreased, but the conductivity increase, should we analyze more other ions? or something we neglected? 
ps. the concentration of H+(25.1 ppm) after resin is calculated from the pH value (pH 1.6).
Thanks all.
ResinConductivity
(us/cm)pHCa2+
(mg/L)Mg2+
(mg/L)K+
(mg/L)Na+
(mg/L)H+
(mg/L)Cl-
(mg/L)SO42-
(mg/L)before                2,739 8.286.969.92.2484.70.0635.9324.9after                8,7421.60.30.10.16.125.1843.89.2

Richard Woodling · Answer

PH problem, either rinse down better after regeneration or convert to sodium form.

Ian Pearson · Answer

There is no direct relationship with conuctivity and pH, however it is the case that Conductivity is related to ionic mobility, which is higher if the ion is smaller. For example, the highest conductivity is given by H3O+. So the lower the pH, the higher the conductivity. It is also the case that  there is a conductivity minimum at neutral pH.  It seems then that your high conductivity is related to the very low pH (and hence very high concentration of H3O+ ions).

Resin	Conductivity (us/cm)	pH	Ca2+ (mg/L)	Mg2+ (mg/L)	K+ (mg/L)	Na+ (mg/L)	H+ (mg/L)	Cl- (mg/L)	SO42- (mg/L)
before	2,739	8.2	86.9	69.9	2.2	484.7	0.0	635.9	324.9
after	8,742	1.6	0.3	0.1	0.1	6.1	25.1	843.8	9.2

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