The unique, compact and easy-to-operate AquapHOx platform is a flexible solution for many underwater applications. Besides stand-alone loggers with internal data storage for long-term deployment, we also offer transmitters for fast sampling / water column profiling and easy integration into consisting set-ups utilizing the integrated analog outputs or RS485- Modbus interface.

The one-channel AquapHOx long-term logger APHOX-LX and real-time transmitter are available with a titanium housing for deep-sea applications down to 4000m. These devices are highly flexible concerning choice of analyte and sensor format, and work with all underwater (-SUB) O2 and total scale pH sensors from PyroScience. With the same device, subsequent measurements of dissolved oxygen and ocean/seawater pH on the total scale are possible.

For applications in shallow water environments, AquapHOx longterm loggers and realtime transmitters with a POM housing are available, which can be deployed down to 100m water depth. These shallow-water devices are dedicated to one analyte, APHOX-L-O2 and APHOX-T-O2 to oxygen and APHOX-L-pH and APHOX-T-pH to pH, but feature the same flexibility concerning optical sensor formats (e.g. sensor caps or fiber-based probes).


All AquapHOx devices have one optical pressure-stable sensor port that is compatible with a variety of optical oxygen and pH sensor heads:

  • ultra-fast optical O2 sensors: (ultra-)high speed sensor caps & minisensors (option -HS-SUB and -UHS-SUB) for fast water column oxygen profiling or aquatic Eddy Covariance measurements
  • full range oxygen sensor caps OXCAP-SUB with additional protective cage to ensure robustness against mechanical impact in general oceanographic applications and long-term underwater deployments
  • new ultra-trace oxygen sensor cap UTROXCAP-SUB (pre-calibrated) with outstanding low detection limit (0.04 µg/L, 0.0013 μmol/L), for high precision measurements in oxygen minimum zones or during ocean deoxygenation events

And new optical sensor for seawater / ocean pH

  • total scale pH sensor cap PHCAP-PK8T-SUB (pH range of 7.0-9.0) requiring no reference electrode, leading to a minimized effect of high ionic strength, suitable for long-term total scale pH measurements in seawater
    With the AquapHOx devices stand-alone operation and real-time measurements can be performed in various oceanic and aquatic habitats like open ocean, the deep sea, diverse coastal ecosystems (mangroves, estuaries, mudflats, kelp forests, seagrass meadows, salt marshes, intertidal zone, oyster reefs, coral reefs), rivers, lakes and water reservoirs.

The new one-device-solution AquapHOx-LX has been already applied successfully in diverse coastal habitats, including coastal water (North Sea, Adriatic Sea), on a reef flat of the Great Barrier Reef of Australia and bivalves growing in oligotrophic seas (Eastern Mediterranean, Israel), sediment incubations in shallow waters in the Baltic Sea, blue mussels growth in a Norwegian Fjord-Coastal System.


Brochure Logger

Brochure Transmitter

Applicable Oxygen Sensor Types



Applicable pH Sensor Types


Related Peer-Reviewed Publications

A high-resolution submersible oxygen optode system for aquatic eddy covariance
Granville et al. 2023, Limnology and Oceanography

High Net Primary Production of Mediterranean Seagrass (Posidonia oceanica) Meadows Determined with Aquatic Eddy Covariance
Koopmans et al., 2020, Frontiers in Marine Science: Marine Ecosystem Ecology

Closing the oxygen mass balance in shallow coastal ecosystems
Long et al., 2019, Limnol. Oceanogr.

A versatile optode system for oxygen, carbon dioxide, and pH measurements in seawater with integrated battery and logger
Staudinger,2018, Limnology and Oceanography: Methods

Surface gas exchange determined from an aquatic eddy covariance floating platform
Long et al., 2018, Limnol. Oceanogr. Methods

Estimation of net ecosystem metabolism of seagrass meadows in the coastal waters of the East Sea and Black Sea using the noninvasive eddy covariance technique
Lee et al., 2017, Ocean Science Journal

In situ quantification of ultra-low O2 concentrations in oxygen minimum zones: Application of novel optodes
Larsen et al., 2016, Limnology and Oceanography: Methods

Oxygen metabolism and pH in coastal ecosystems: Eddy Covariance Hydrogen ion and Oxygen Exchange System (ECHOES)
Long et al., 2015, Limnology and Oceanography: Methods

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