An attempt to reduce the fogging of the windows, this was a fail.  The obvious problem was the water level sensor couldn't detect it & failed negative.  It doesn't conduct electricity.

The less obvious problem was the transducers leaking like crazy.  Maybe electrostatic potential was required to aid the mechanical oscillation in accelerating water or maybe the electrostatic potential was keeping the water on 1 side.  Something about the conductivity of tap water is required for the transducers to work efficiently. 

So back went tap water & it worked perfectly again.  There might be some additive which can create the required conductivity without fogging windows.

A bit surprising that the cleanest water in the world from the mokelumne river still has enough impurities to make a difference.