Pyxis ultra low conductivity sensors

Pyxis ST-725 Inline Conductivity Sensor

The Pyxis Lab industrial grade in-line ultra-low conductivity sensors are specially designed for pure and ultra-pure water applications

The Pyxis Lab ST-724, ST-725 and ST-728 are ‘smart sensors’ with a built-in transmitter supporting digital & analog signal outputs, and are designed to simplify field installation, calibration and operation.


  • Two 4-20 mA analog outputs temperature and conductivity
  • RS-485 digital output for conductivity and temperature
  • Calibration and diagnostics by uPyxis app via Pyxis MA-CR Bluetooth adapter
  • Rugged all stainless steel and Hastelloy construction
  • Three sensor range options available

Installation & calibration

The sensors offer simple ¾” MNPT threaded installation or installation in the Pyxis inline tee assemblies and are constructed with a Hastelloy electrode tip and stainless-steel body.

All three models can be wirelessly calibrated with uPyxis app for mobile or desktop devices when used with the MA-CR Bluetooth adapter. The sensors both offer two 4-20mA Analog outputs, one for conductivity and one for temperature, as well as RS-485 Modbus output for a broad array of installations that desire to connect the smart sensor directly to receiving controller, PLC or DCS network. Sensors have built-in RTD for the automatic compensation of sample temperature.


Typical applications

The Pyxis Lab ST-724, ST-725 and ST-728 are industrial grade in-line ultra-low conductivity sensors specially designed for pure, ultra-pure and de-ionised water applications, including:
  • Boiler feed water and condensate
  • RO and EDI/EDR process water
  • Ion exchange
  • Distillation
  • Semi-conductor cleaning
  • Degas conductivity and other process applications

Key information

ModelRangePrecisionTemp (°C)
µS /cm
± 0.2 µS/cm or
±1% (<500 µS)
± 2% (>500 µS)
0 - 100
µS /cm
± 0.1 µS/cm or
1% of value
0 - 100
µS /cm
± 0.1 µS/cm or
1% of value
0 - 100

Related products

  • Walchem WEL series pH ORP electrode

    Contacting conductivity
    Low cost CPCV or stainless steel

  • Pyxis ST-720

    High range conductivity
    Smart and robust for industrial applications

  • Robust conductivity
    Stainless steel for high pressure & temperatures

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Custom build solutions

Redefine simplicity and flexibility in cooling tower solutions with our plug-and-play service that delivers rapid installation.

We offer standard layout that serves as a solid foundation but we can be customise to meet the unique needs of any client site. We tailor the build to achieve optimal performance.

Our custom builds are popular as a comprehensive solution that's wired and seamlessly integrated meeting any site requirements. Email us today to learn more about our bespoke custom built solutions to speed up your installation and reduce operation or project downtime.


We specialise in delivering tailored product training to empower your team and enhance operational efficiency. Whether you prefer on-site sessions, at your company's location or the convenience of video conferencing, we've got you covered.

Our focus revolves around installation best practices, ensuring seamless product connectivity, and optimising maintenance procedures. Take the first step towards maximising your team's potential. Email us today to learn more about our bespoke training offerings, check availability, and embark on a journey to enhance your team's expertise.

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Sensys Ltd

Head Office
24 Vision Park
Preston Place
Upper Caldecote
SG18 9GQ

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01438 759 595

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