Hello again Rahm,
I believe what you are looking for are sensors and a system to measure the conductivity or resistivity of clean water.
Take a look at this web page from Foxboro .
resource.invensys.com/instrumentation/sp...pss/6/6-3/6_3c2b.pdf
As is stated in the brochure:
"The 871CR Series Sensors measure the conductivity or resistivity of a solution. These sensors, together with an 870ITCR Intelligent Electrochemical Transmitter or an 875CR Intelligent Electrochemical Analyzer, are used in a broad range of applications including critical ultrapure water resistivity measurements found in the semiconductor industry and conductivity measurements used in power and pharmaceutical water measurements."
Is one of these sensors and the electrochemical analyzer the equipment you are looking for?
Regards
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com
519 641- 3212