Conductivity / TDS

Conductivity is the measure of liquid concentrations. They are expressed in uSiemens or mSiemen, where 1 mSiemen equal to 1,000 uSiemen. Conductivity readings are widely used for gauging mixture concentrations and chemical compound. It does not measure specific salts but the total combine salts in the liquid, making it the fastest non-destructive test available. Conductivity is also expressed in TDS (Total Dissolved Solid), and the unit of measurement is in ppm (1 mili-gram of solid dissolved in 1 litre of water).
The converstion factor for TDS varies for each type of chemical. In municiple water measurement, a factor of 0.5 is generally used to convert readings from conductivity, where 1 ppm equal to 2 uSiemen.