
Overview
The ST-772 dissolved oxygen (DO) sensor is based on the principle of fluorescence quenching to determine the dissolved oxygen content in water. It incorporates Pyxis’ advanced technology in the field of fluorescence detection and uses dual light source detection technology with excitation and reference light sources, offering a wide detection range and low detection limit. The sensor integrates temperature and pressure sensors, which can perform temperature and pressure compensation for the measurement of dissolved oxygen based on ambient environmental conditions present in the application of use. The ST-772 offers both 4-20mA and RS-485 Modbus outputs and is Bluetooth enabled when used in conjunction with the MA-CR Bluetooth Adapter. The ST-772T model is designed to be installed inline and includes the ST-001 tee, while the ST-772 model is for submersion installations.
Key Benefits
- 0.004-20 mg/l measurement range
- Simple DO membrane cartridge replacement every 2 years
- Extremely scratch-resistant membrane
- Accurate and stable measurement – no calibration for up to 2 years
Typical Applications
- Activated Sludge / Aerated Basin
- Wastewater & Sewage Processing
- Chemical & Process Water Applications
- Domestic Water Applications
- Filtration Applications
- Aquaculture
- Agriculture

Pyxis Ultra-Low Dissolved Oxygen Sensors
The ST-774 is the culmination of years of extensive research and development at Pyxis Lab and incorporates a fully optical platform measuring ultra-low residuals of dissolved oxygen via Blue and Red Light sources, commonly referred to as fluorescent quenching. The ST-774 is a fully integrated state of the art smart sensor that comes calibrated from the Pyxis factory enabling rapid deployment and simple maintenance and calibration for years of service. Designed specifically for cooled sample applications measuring ultra-low concentrations (0.4 to 2000 PPB) of dissolved oxygen the ST-774 is un-matched in the industry and is ideal for water and process applications requiring the utmost accuracy and range of detection.
Key Benefits
- 0.4-2,000μg/L measurement range
- Built-in temperature and pressure sensors
- Accurate and stable measurement with ultra-low drift
- Built-in transmitter without the need of using a preamplifier or meter head
Typical Applications
- HP Boiler Feedwater / Deaerator Storage
- Power Facilities
- Ultra-Pure Water
- Closed Loops
- Condensate Return
- Beverage Production / Post Fermentation
- Semiconductor Rinse Water