Pyxis ST-765SS Series Oxidizer and pH Sensors (ClO2, Ozone, Sulfite, Bromine, Free Chlorine + Sulfite)

The Pyxis ST-765SS platform applies the membrane-less, bare-gold electrode architecture of the ST-765SS-FCL free chlorine and pH sensor to five further oxidizer and parameter combinations. All models share the same 304 stainless steel body, the replaceable EH-765 reference electrode head, dual 4-20 mA and RS-485 Modbus outputs, and wireless calibration through the uPyxis app with the MA-CR Bluetooth adapter. In Turkey, Mikron Proses (Üsküdar, Istanbul) provides application consulting on model and flow cell selection.

Parameter selection · Flow cell (FR-50 / FR-300-PLUS / ST-007) → Send us your requirement

For the plastic-bodied ST-765P and the ST-766SS series with ORP and conductivity, see the ST-765P and ST-766SS oxidizer sensors. For more Pyxis inline sensors, see Online Analyzers.

ST-765SS-CLO: chlorine dioxide + pH

The CLO model is published in the same datasheet as the FCL (ST-765SS Series pH + Oxidizer Sensor Data Sheet). It measures chlorine dioxide in the range 0.00-5.00 ppm together with pH; the accuracy and compensation logic are identical to the FCL (±0.01 mg/L or 1%, pH-compensated up to pH 9.0). It can be ordered with the standard FR-50 flow reservoir (P/N 53608) or as a sensor only (53608-NFR). As for the FCL, an OxiPanel IK-765SS-CLO panel pre-assembled with the UC-50 terminal is also available.

ST-765SS-O3: ozone + pH

The O3 model, documented in its own datasheet, measures ozone in the range 0.00-2.00 ppm. The manufacturer lists bottled water filler production, spring water transport disinfection, food and beverage equipment sanitizing, conveyor and flume water, and irrigation and process water as typical applications.

ST-765SS-SO3: sulfite + pH

The factory standard range of the sulfite model is 0.00-5.00 ppm; it can be extended up to 0-100 ppm in the uPyxis app. The manufacturer states that the sulfite measurement is consistent with wet chemistry methods. Typical applications are chlorine removal in RO feedwater, chlorine removal in wastewater effluent (when used with the FR-300-PLUS), and oxygen scavenger monitoring in boiler feedwater and blowdown.

ST-765SS-Br: bromine + pH

The bromine model measures in the range 0.00-5.00 ppm and is intended for cooling and process water applications. The manufacturer states that in challenging or dirty water applications this sensor should be used only with the FR-300-PLUS auto-brushing flow reservoir.

ST-765SS-DCL: free chlorine + sulfite + pH (dual measurement)

The DCL model produces four separate values from its four-electrode design: free chlorine (0.00-5.00 ppm), sulfite (0.00-100.00 ppm, auto-range), pH and temperature. With one sensor, both the residual chlorine and the dosed sulfite or oxygen scavenger can be verified at the same time; the manufacturer designed it for dechlorination (chlorine scavenger) treatment. In clean water applications it is used with the ST-007 stainless steel tee, and in dirty water applications with the FR-300-PLUS auto-brushing flow reservoir.

Which oxidizer parameter (ClO2, ozone, sulfite, bromine or the free chlorine plus sulfite pair) and which flow cell (FR-50, FR-300-PLUS or ST-007) suits your process depends on water quality and the existing automation infrastructure. Tell us your requirement and we will select the right model combination together with you.