| pH Sensor | How acidic or alkaline the water is, reported on the pH scale. | Continuous tracking of pH in a pool circulation line or monitoring system. | Helps identify changes that can affect swimmer comfort, sanitizer performance, and water balance. | Requires routine calibration and cleaning. It does not measure sanitizer concentration. |
| Oxidation-Reduction Potential (ORP) Sensor | The water’s oxidation-reduction potential, reported in millivolts. | Ongoing indication of the water’s oxidizing conditions, often used alongside pH monitoring. | Provides a continuous trend that can help operators spot changes in disinfection conditions. | ORP is not a direct measurement of free chlorine. Readings are influenced by pH, temperature, and other water conditions. |
| Amperometric Chlorine Sensor | Free chlorine or another specified chlorine parameter, depending on the sensor design. | Continuous sanitizer monitoring in systems designed for the sensor’s chemistry and operating conditions. | Measures a chlorine-related parameter directly rather than relying on ORP as a proxy. | Sensor type, pH compensation, flow requirements, and maintenance needs vary. Confirm that the device is suitable for pool water. |
| Conductivity Sensor | Water’s ability to conduct electrical current, which is related to dissolved ions. | Monitoring changes in dissolved ionic content, especially in pools where salt or water balance is tracked. | Can reveal broad changes in the water’s ionic content over time. | Conductivity does not identify individual substances and is not a substitute for testing sanitizer, pH, or specific dissolved chemicals. |
| Temperature Sensor | Water temperature. | Continuous tracking of pool temperature and temperature changes that may affect water management. | Simple, ongoing measurement that can provide useful context for interpreting other readings. | Temperature alone does not indicate whether pool water is safe or properly sanitized. |
| Multi-Parameter Sensor System | Two or more parameters, commonly selected from pH, ORP, chlorine, conductivity, and temperature. | Centralized, ongoing monitoring where multiple water conditions need to be viewed together. | Combines readings in one monitoring setup and makes it easier to review trends. | Each measurement has its own accuracy, calibration, and maintenance requirements. Verify which parameters are directly measured. |