Showcase your capabilities
If you design, build or supply Multiparameter Sondes, create a profile to showcase your capabilities and connect with visitors who have an active requirement for your solutions.
Suppliers of Multiparameter Sondes
AML Oceanographic
Hydrographic & Oceanographic Equipment for Unmanned & Autonomous Surface Vessels & Underwater Vehicles
Silver Partner
Multiparameter Water Quality Sondes
Overview of Multiparameter Sondes for USV, ROV & AUV
Introduction to Multiparameter Sondes
Multiparameter sondes are submersible instruments designed to measure several water quality parameters simultaneously. A multiparameter water quality sonde combines multiple sensors within a single instrument, providing measurements such as temperature, conductivity, salinity, Dissolved Oxygen (DO), pH, and turbidity. Additional sensors may measure fluorescence, selected dissolved ions, and water pressure.
Water quality sondes are used in freshwater, coastal, and marine environments for environmental monitoring, scientific research, and water quality assessments. They support handheld field surveys, continuous monitoring installations, vertical water column profiling, and integration with unmanned marine systems. Depending on the configuration, onboard electronics process and store sensor readings for autonomous logging or transmit measurements through connected telemetry systems.
Sensors Used in Multiparameter Sondes
Optical Dissolved Oxygen Sensors
Optical dissolved oxygen sensors use luminescence-based measurement techniques to determine oxygen concentration. Oxygen quenches the luminescent response of a sensing material, allowing the instrument to calculate DO without consuming oxygen during measurement. These sensors are widely used in long-term environmental monitoring.
Electrochemical Dissolved Oxygen Sensors
Electrochemical DO sensors measure an electrical current associated with oxygen reduction at an electrode. Common configurations include polarographic and galvanic sensors. Measurement performance depends on factors such as membrane condition, electrolyte maintenance, and sufficient water movement around the sensing surface.
Glass Electrode and Solid-State pH Sensors
Glass electrode pH sensors measure electrical potential relative to a reference electrode to determine pH. Alternative solid-state sensing technologies may also be used in compatible sonde configurations. Regular calibration using reference buffer solutions helps maintain measurement accuracy.
Conductivity Cell Technologies
Conductivity sensors determine the electrical conductance of water using electrode-based or inductive measurement principles. Instruments apply cell calibration and temperature compensation to report conductivity, temperature-corrected specific conductance, and supported derived salinity values.
Optical Turbidity Sensors
Optical turbidity sensors detect light scattered by suspended particles in water. Sensor geometry and measurement wavelength influence performance, particularly where particle size, composition, and concentration vary. Regular cleaning helps maintain reliable measurements by reducing interference from deposits on optical surfaces.
Fluorescence-Based Water Quality Sensors
Fluorescence sensors emit light at selected wavelengths and measure the resulting fluorescence from target substances. Common applications include chlorophyll-a, cyanobacterial pigment, and fDOM monitoring. Measurements can be affected by temperature, turbidity, and other interferences, so fluorescence-based readings generally provide indirect estimates that may require site-specific validation.
Ion-Selective Electrodes
Ion-selective electrodes measure electrical potentials related to the activity of specific dissolved ions. Compatible multiparameter sondes can use these sensors for ammonium, nitrate, or chloride measurements. Calibration, interference from other ions, and sensor response characteristics affect measurement reliability, particularly during prolonged deployment or in saline water.
Integrated Pressure and Temperature Sensors
Temperature sensors use temperature-sensitive electrical components, while pressure sensors measure hydrostatic pressure to estimate depth, with atmospheric pressure accounted for where required. These measurements also support compensation algorithms used by other water quality sensors.
Core Applications of Multiparameter Sondes
Rivers, Lakes, Reservoirs, and Watershed Monitoring
Water quality sondes measure changing environmental conditions in rivers, lakes, and reservoirs. Parameters such as temperature, DO, conductivity, and turbidity help characterize seasonal variation, sediment transport, and changes associated with rainfall or runoff. Fixed sondes also support continuous watershed monitoring programs, providing measurements over extended periods.
Coastal, Estuarine, and Oceanographic Profiling
Marine-compatible sondes measure water quality in coastal environments and estuaries, where salinity, temperature, and dissolved oxygen can vary considerably. Depth-rated instruments can collect vertical profiles to investigate water column stratification, freshwater mixing, and oxygen distribution.
Groundwater, Boreholes, and Drinking Water Sources
Compact multiparameter sondes are used for groundwater measurements in monitoring wells and boreholes. Conductivity, pH, DO, and ORP measurements help characterize groundwater conditions and investigate changes in water chemistry. These instruments also support monitoring of raw water sources used for drinking water supply.
Aquatic Ecosystems, Wetlands, and Habitat Assessments
Environmental monitoring programs use sondes to evaluate water conditions affecting aquatic organisms and habitats. Dissolved oxygen, temperature, pH, and conductivity measurements contribute to assessments of ecological conditions in wetlands, freshwater habitats, and coastal ecosystems.
Aquaculture Water Quality and Harmful Algal Bloom (HAB) Monitoring
Aquaculture facilities use water quality sondes to monitor DO, temperature, salinity, and pH in production environments. Sondes equipped with fluorescence sensors can also support Harmful Algal Bloom (HAB) monitoring by detecting changes in chlorophyll-a or selected cyanobacterial pigments. These measurements provide indirect indicators of potential bloom activity and may require confirmation through additional analysis.
Pollution Investigations and Environmental Impact Assessments
Multiparameter sondes support investigations of water quality changes associated with industrial discharge, construction activity, sediment disturbance, and other environmental pressures. Continuous measurements help identify variations over time, while mobile surveys can examine spatial differences around potential pollution sources.
Integration with Unmanned Marine Systems
Multiparameter water quality sondes can be integrated with unmanned marine platforms to collect environmental measurements during autonomous or remotely controlled operations. Integration requirements include instrument dimensions, pressure ratings, electrical power, communication interfaces, and synchronization with platform navigation data.
- Integration with Unmanned Surface Vessels (USVs): USVs can carry submerged sondes for water quality mapping across lakes, reservoirs, rivers, and coastal waters. Measurements can be associated with vessel position to create georeferenced environmental datasets.
- Integration with Autonomous Underwater Vehicles (AUVs): AUV-mounted sondes collect water quality measurements along underwater survey routes and at different depths. Their measurements support investigations of water column structure, oxygen distribution, and environmental gradients.
- Integration with Remotely Operated Vehicles (ROVs): ROV-mounted sondes provide water quality measurements during underwater inspections and localized environmental surveys. Operators can position the instrument near specific underwater features or areas of interest.
Integrated sondes can complement Conductivity, Temperature, and Depth (CTD) instruments, sonar, and navigation systems, although some measurements overlap with CTD functions.
Biofouling Prevention & Long-Term Deployment
Biofouling is an important consideration when multiparameter sondes remain submerged for extended periods. Biological growth and sediment accumulation can interfere with sensor surfaces, reducing measurement reliability and increasing maintenance requirements.
- Biological Fouling of Water Quality Sensors: Algae, microorganisms, and other aquatic organisms can accumulate on exposed sensing surfaces during continuous deployment, potentially affecting measurement accuracy.
- Mechanical Wipers and Automated Cleaning Systems: Integrated wipers or cleaning mechanisms remove deposits from compatible sensor windows and help maintain optical measurement performance.
- Copper-Based Antifouling Components: Copper guards and other copper components may inhibit biological growth around exposed sensors, subject to environmental and deployment requirements.
- Protective Sensor Guards and Flow Considerations: Sensor guards provide mechanical protection, while appropriate water circulation helps reduce stagnant conditions around measurement surfaces.
- Biofouling Effects on Optical and Electrochemical Measurements: Accumulated deposits can obstruct optical paths, affect membrane-based measurements, and introduce localized changes in water chemistry.
- Maintenance Scheduling for Extended Deployments: Routine inspection, cleaning, calibration verification, and sensor replacement help maintain data quality throughout long-term monitoring programs.
Antifouling measures can extend servicing intervals, but periodic inspection and calibration verification remain necessary for dependable measurements.
Water Quality Monitoring Standards
Water quality monitoring programs may reference International Organization for Standardization (ISO) standards covering sampling procedures and specific measurement methods. Their applicability depends on the measured parameter, sensor technology, and intended application.
- ISO 5667 Series: Provides guidance and requirements relating to water sampling, including sampling program design and procedures relevant to environmental monitoring.
- ISO 5814: Specifies an electrochemical probe method for determining dissolved oxygen in water.
- ISO 17289: Specifies an optical sensor method for determining dissolved oxygen using fluorescence quenching.
- ISO 10523: Covers the determination of pH in water using an electrochemical method.
- ISO 7027 Series: Addresses turbidity determination, including quantitative optical methods under ISO 7027-1.
- ISO 7888: Specifies an electrical conductivity measurement method for water.
Calibration procedures, field checks, and quality assurance records are also important for interpreting data collected by multiparameter sondes. Reference to a particular standard does not necessarily indicate that an instrument has been independently certified or that every deployment meets the specified method.
Developments in Multiparameter Sonde Technology
Multiparameter sonde technology continues to develop in response to requirements for autonomous monitoring, improved sensor integration, and more efficient environmental data collection.
- Expanded Sensor Integration: Modular instrument designs support additional optical and chemical sensor options, including ultraviolet nitrate measurement in compatible models.
- Antifouling Improvements: Automated wipers and protective designs continue to be refined to reduce maintenance requirements and maintain sensor performance during extended deployments.
- Autonomous Environmental Monitoring: Integration with USVs, AUVs, and other robotic platforms supports automated water quality surveys and measurements in difficult-to-access locations.
- Automated Data Quality Control: Monitoring software can flag abnormal readings and missing measurements, while calibration records and field checks remain necessary to identify and assess sensor drift.
These developments support more integrated approaches to freshwater, coastal, and marine water quality monitoring, particularly where continuous measurements and autonomous data collection are required.
