Moored pH Ocean Monitoring Systems
Our Moored pH Ocean Monitoring Systems
Ocean pH plays a critical role in the health of the global ocean due to the short timescales relevant to biological activity. With recent studies highlighting the impacts of acidification on the carbon cycle as well as on coral, shellfish, phytoplankton, and zooplankton, long-term monitoring of local pH conditions is vital to support data-based decisions regarding human behavior and conservation efforts (NOAA Ocean Acidification).
Sea-Bird Scientific recognizes the need for robust, reliable in-situ and high-quality moored pH instruments. We offer two solutions that are state-of-the-art, multi-parameter systems with integrated flow paths that provide better correlation of measurements and sampling, as well as manufacturer-supplied software that allows the user to set up the sensor, monitor graphical data in real time, upload stored data, and process that data.

Shallow SeaFET™ V2 | Fully Autonomous Ocean pH Sensor
The Shallow SeaFET™ V2 Ocean pH sensor uses the ISFET technology for stable, long-term pH measurements in salt water. The pH sensor has been used extensively around the globe for ocean acidification research, coral reef research, coastal marine biology and environmental monitoring. The SeaFET™ V2 Ocean pH sensor is fully autonomous with internal power, sample scheduling and data logging capabilities.
Features and Applications
- Flexible operation
- Internal data storage and batteries
- Calibrated using natural seawater
- Ocean acidification research
- Coral reef research
- Coastal marine biology
- Environmental monitoring
Shallow SeapHOx™ V2 | Multiparamater Moored System
The Shallow SeapHOx™ V2 system is comprised of the SeaFET™ V2 Ocean pH sensor and the SBE 37-SMP-ODO MicroCAT CTD+DO sensor. This new system allows for collection and combination of pH data and critical oceanographic/biological measurements of temperature, salinity, and oxygen. The integrated package also enables the SeaFET™ V2 to take advantage of the MicroCAT’s pumped flow path and anti-fouling technology, extending deployment durations.
Features and Applications
- pH, Conductivity, Temperature, Pressure (optional), and Optical Dissolved Oxygen, at user-programmable intervals
- Integral pump
- RS-232 communications
- Internal memory and batteries (can be powered externally)
- Industry-leading conductivity cell biofouling protection
- UCI software package (setup, data upload, and data processing)
- Field-proven MicroCAT CTD family has more than 10,000 instruments deployed worldwide
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HydroCAT-EP V2 | Long-term Monitoring in Both Saltwater and Freshwater
The Sea-Bird Scientific HydroCAT-EP V2 is a moored CTD instrument suited for long-term deployments in biologically rich, coastal environments. The HydroCAT-EP V2 can be utilized in both saltwater and freshwater.
The HydroCAT-EP V2 integrates seven field-proven sensors that are factory and/or field-calibrated (pH only) to provide optimal accuracy and long-term data stability. With optional optical dissolved oxygen, chlorophyll, turbidity, and pressure sensors, the HydroCAT-EP V2 provides a solution for any ocean, coastal, or freshwater application. It has an integrated pump that operates each time the system takes the measurements, flushing the measured water and quickly moving new water into the flow path to achieve measurements at the highest accuracy.
The HydroCAT-EP V2 uses a field-serviceable and replaceable glass-electrode sensor to measure pH to an initial accuracy of ± 0.1 pH. Like many glass-electrode pH sensors, it is deployable in freshwater and marine environments and can be calibrated in the lab or field with standard, clear pH buffer solutions. Unattended, the HydroCAT-EP V2 can measure up to 3 months of high-quality pH data while retaining stability for at least 1 year for all other sensors. This timeline reduces overall field servicing costs and data gaps.
Features and Applications
- multi-parameter CTD-DO-pH at depths up to 350m | Case Study
- ocean acidification
- carbon cycle
- deoxygenation
- environmental monitoring | Case Study
- fisheries and aquaculture | Case Study
- water quality | Case Study
- fresh or saltwater deployments
Training

Deep SeapHOx™ V2
The Deep SeapHOx™ V2 is suited for long-term deployments in a range of environments, from coastal regions to the deep ocean offshore.
The Deep SeapHOx™ V2 integrates the Deep SeaFET pH Sensor with the SBE 37 SMP-ODO MicroCAT CTD+DO sensor to provide a multiparameter biogeochemical monitoring tool for ocean acidification and other physical and biological ocean processes, which is available in either 350 or 2000 meter depth ratings depending on the application. The Deep SeapHOx™ V2 allows for simultaneous data collection of pH with the critical oceanographic and biological measurements of temperature, salinity, pressure, and oxygen.
The Deep SeapHOx™ V2 utilizes internal memory and power provided by batteries and/or external power to operate autonomously for a long-term deployment. It has an integrated pump that operates each time the system collects the measurements, flushing the measured water and quickly moving new water into the flow path to achieve measurements at the highest accuracy.
The Deep SeapHOx™ V2 utilizes a solid-state ion selective field effect transistor (ISFET) that is adapted for use in surface to high pressure environments. Unattended, the Deep SeapHOx™ V2 can measure high-quality data and retain stability for at least 1 year for all integrated sensors. This timeline reduces overall field servicing costs and data gaps.

Features and Applications
- multi-parameter CTD-DO-pH at depths up to 2000m | Case Study
- long-term stability
- ocean acidification
- climate research
- marine biology
- carbon cycle
- deoxygenation
- ocean monitoring
- deep sea corals
- food web research