Greg, you could get a conductivity meter and ask the client to send a water sample, so you will know the results to expect. Look for a DIST WP3 tester. It is from 10 to 1990 micro mhos or micro siemens. They are only about $60. You just put it in the water and hold a spring loaded button down for reading. It is very accurate. We use it for mixing up ship gyroscope fluid where the gyro sphere is floating in liquid and the motors get current thru the liquid. Not sure where it was purchased, but saw on on line from Canada for 89 CAD.
