Answer from Suhas,

All connecting pipes are silicon though some metallic threaded Connections are used no direct metallic connection Pump is magnetic driven all plastic body and moving parts standing 120 deg C temp

The chemical is falling not continuously

In contact with solution inside but sprayed in air to fall below in foam on the side in solution temps are around 90deg C
This is the fact
If that still gives negative current may be
Perhaps some very small due to foam -highly resistive conduction
I am not plating expert