Overview of water quality measured in surface waters all over The Netherlands. Data are provided on electric conductivity (EC, ppm and µS), pH and temperature (T, degrees Celsius). 

legend: The icons numbers are based on EC (ppm) classes, with 0: EC<100, 1: EC between 100-199, 2: EC between 200-299, etc

My device gives EC readings in ppm. I used calibration curves to also give the values in µS. One curve for 0-200 ppm and another for >200 ppm.

legend: The icons numbers are based on 0.5 unit pH classes. NA= no data available.