Pyxis disinfection sensors

Pyxis ST-765 Inline Sensor

The ST-765SS series are stainless steel, non-wet chemistry oxidiser + pH + temperature sensor series.

The ST-765SS series are stainless steel multi-parameter membrane-less sensors based on unique electrochemical principles to determine free chlorine or chlorine dioxide and pH content in water. These sensors incorporate Pyxis Lab® advanced technology in the field of bare-gold electrochemical detection.


The ST-765SS-FLC and ST-765SS-CLO sensors include a range of measurements:
  • Free chlorine
  • Chlorine dioxide
  • Monochloramine
  • Bromine
  • Sulfite
  • Ozone
  • pH
  • Temperature


  • Real-time pH + FCl (0-5ppm) or ClO2 (0-5ppm) detection
  • Dual 4-20mA outputs (FCl or ClO2 + pH) and RS-485
  • Bluetooth® enabled with the MA-CR adapter
  • Wireless uPyxis® calibration and cleanliness diagnostics
  • Integrated RTD & pH compensation to pH 9.0 of the oxidiser value
  • Replaceable EH-765 reference electrode assembly – simple maintenance


Typical applications

  • Industrial process
  • Cooling water
  • Fresh / brackish / sea water
  • Raw / influent water
  • Wastewater effluent
  • Surface water / storm water

Product information

WDP Intuition 6 - NEW

The ST765SS is now available off the shelf as part of 2 turnkey systems for use in more difficult disinfection applications.

Stable and accurate control of oxidisers can be achieved even in applications where the pH, temperature, pressure or flow rate is fluctuating. The Intuition-6 has been paired with Pyxis sensors and accessories to create the WDP Intuition 6 - providing you with confidence that your process is under control.

Keep challenging applications operational

The addition of the Pyxis FR-300 and ST-765SS to the Intuition 6 provides constant cleaning, monitoring and control, by brushing the flow assembly. Designed to keep systems running in challenging applications containing fats, oils and grease.
More info:

Drinking water disinfection

Combining the versatility and reliability of Walchem's Intuition 6 with the Pyxis ST-765SS, and FR-50 provides display, data logs and relay activation of dosing pumps/valves, designed for use in swimming and hydrotherapy pools as well as domestic & drinking water applications.
More info:

Related products

  • Walchem disinfection sensors

    Non-membrane disinfection
    For high pressure, high temperature applications

  • Walchem disinfection sensors

    Membrane disinfection
    Cost effective & reliable amperometric disinfection sensors

  • Pyxis ST-500 Inline Sensor

    Bleach/chlorine dioxide
    Measure the optical density of bleach or chlorine dioxide

You may also need...

  • Intuition-9
    Powerful control with 24 inputs & 12 outputs

  • Intuition-6
    Remote communication with 4 inputs & 6 outputs

  • W100
    1 sensor input & 3 control outputs, wall mount design


  • Pyxis FR-300

    Motorised brush flow assembly for cleaning of the ST-765SS series

  • Dosing tanks and bunds

    Dosing tanks & bunds
    Round or rectangular in a range of capacities from 25 to 1,000 litres.

  • Pyxis MA Series

    MA Series
    Inline BlueTooth® 5.0 wireless adapters

  • Pyxis MA Series

    Pyxis PowerPACK series BlueTooth® auxiliary adapters



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.

Request support

Follow us on LinkedIn

Sensys Ltd

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

what3words: ///uptown.wisley.guests

01438 759 595

Join our mailing list

Sensys icon

Enquire Now