You might be right Patrick. Conductance is effectivly the amount of ions. I never thought of the H+ ions as conductance effectors. But there are two new problems, first there must have been a dramatic decrease of pH out of nowhere, and second if that was so it had to effect the conductance that much.
Normally the conductance is mainly effected by Ca2+ ions and I think maximum about 80 µS is effected by H+, OH- and HCO3-. So this might be a part of my conducance increase but not the only reason.