Ozone Sensor SM-X

The SM-X ozone sensor was a replacement sensor for the OS-4, OS-6, and A-22.  However, the SM-X is no longer in production and is now obsolete.

SM-X Replacement Sensor

The SM-6 also used the SM-X as a replacement sensor and also no longer available for purchase.

SM-6 with SM-X

The replacement ozone sensor SM-X (also known as the SM-X-20 or SM-X-2) was paired with EcoSensors OS-4 Ozone Switch, OS-6 Ozone Controller, and A-22 Ozone Monitor. The following options are now available instead:

A-22 Ozone Monitor

A-22 Ozone Monitor

The A-22 is obsolete and there is no replacement sensor option available.  We recommend the following as comparable ozone monitor options to replace your A-22:
D-16 with Ozone 0-20 ppm – https://www.oxidationtech.com/d-16-gas-detector.html
S-300 with EOZ 0-10 ppm – https://www.oxidationtech.com/aeroqual-series-300.html

OS-4 Ozone Switch & OS-6 Ozone Controller

OS-4 Ozone Switch
OS-6 Ozone Controller

The OS-4 and OS-6 Ozone Detectors can be upgraded to use the SM-7/SM-EC electrochemical sensor as an ozone replacement sensor to the SM-6/SM-X.  The new SM-7 will need to be connected to the OS-4 and OS-6 via the wired cable.

SM-7/SM-EC Ozone Sensor

There are two range options for the new SM-7/SM-EC sensor: 0-20ppm or 1-50ppm.  Both range options can be used with the OS-6, but only the 0-20ppm can be used with the OS-4. After you have upgraded to the SM-7/SM-EC then only replacing the SM-EC sensor that’s inside of the SM-7 needs to be done for future sensor replacement.

SM-EC sensor module

The SM-7/SM-EC ozone sensors should be replaced annually as the sensor calibration is good for up to 1 year.

Feel free to contact us with any questions that you have about the SM-X ozone sensor being discontinued.

New EcoSensors SM-7 Ozone Sensor

EcoSensors recently released the new SM-7 Ozone Sensor for sale.  This is the first Electrochemical based ozone sensor available from EcoSensors (previous sensors were all HMOS).  This sensor reliably and accurately detects ozone from 0-50 ppm.

SM-7 Sensor with SM-EC

The SM-7 can be used as a stand alone sensor transmissiting module using RS-232 communications.  Or, it can be used with either the OS-6 or OS-4 remote mount sensors from EcoSensors.

OS-6 Ozone Controller
OS-6 Ozone Controller


OS-4 Ozone Switch
OS-4 Ozone Switch

Typical Applications:

  • Laundries using ozone.
  • Large noisy factory environments.
  • Casinos and other ozonated public areas.
  • Agricultural storage areas.
  • Farms.
  • Food processing plants.


  • 25ppb sensitivity with 5ppb resolution.
  • Wide operating range (.02-50ppm).
  • Electrochemical Sensor
  • Wide detection range
  • Low Power
  • Low Maintenance
  • Uses easily available 8-24 VDC power.
  • Small enough to mount almost anywhere.

The SM-EC is an electrochemical ozone sensor module for use with our OS-6 digital instrument. This new technology from Eco Sensors provides accurate ppb-level detection and resolution over a wide (.2-50 ppm) concentration range. The sensor module is compensated for temperature and humidity effects, with little to no cross sensitivity to VOC’s. The SM-EC makes our digital instruments more accurate at both ppb and high ppm levels of ozone, enabling improved monitoring and control for our users.

For more info on this sensor, or any other ozone sensor contact us, we would be glad to put our experience to use for you.