Conductivity, TDS and Salinity Measurement
Understand the relationship between conductivity, TDS and salinity and select a suitable cell and measuring range.
Practical guidance
Conductivity measures the ability of dissolved ions to carry electrical current. TDS is commonly derived using a conversion factor, while salinity uses another relationship. Select a cell constant and range suitable for the sample. Rinse the cell, remove trapped bubbles, allow temperature compensation and use conductivity standards close to the operating range.
Recommended routine
- Review the product manual and required standards.
- Inspect the instrument, cables and sensor condition.
- Calibrate at suitable points using fresh standards.
- Rinse and condition the sensor before measuring.
- Allow the reading to stabilise without contaminating the sample.
- Record the result together with temperature and calibration status.
- Clean and store the sensor correctly after use.
Frequently asked questions
How often should an instrument be calibrated?
Calibration frequency depends on sensor stability, application risk, sample type and quality procedure. Critical measurements may require calibration before each batch or shift.
Can the same sensor be used for every sample?
No. Sensor material, range, temperature and chemical compatibility must match the sample and application.
When should a reading be confirmed?
Confirm readings that are unexpected, safety-critical, near a specification limit or inconsistent with process conditions.