Ozone Analyzer

Ozone Analyzer – OzoSense

The OzoSense online Dissolved Ozone Analyzer from Pi for the measurement of ozone concentration in water, is designed to be simple to install and operate, and offers unrivalled stability, accuracy and precision, whilst offering excellent value for money.

The OzoSense range of Ozone Analyzers, Ozone Controllers and Ozone Monitors utilize the very latest and best ozone sensors available in the world today. They are membrane devices which are insensitive to changing pH, use no reagents, are extremely stable, and have reduced maintenance and reduced whole life costs.

The ozone sensors connect to the range of electronic instrument controllers from Pi resulting in world class online dissolved ozone controllers and analyzers. For more information on Pi’s controllers, click here.

Dissolved Ozone Analyzer

Dissolved Ozone Analyzer – Sensor

The membraned amperometric ozone sensors are two electrode sensors which operate at an elevated applied potential which in turn eliminates zero drift. Its unique design means that no reagents or buffers are required at all.

Ozone Monitor

Ozone Monitor – CRONOS

  • Stable and reliableexcellent process control – ozone controllers
  • Suitable for all potable, process and salt waters
  • Up to 6 months between maintenance
  • Up to 3 months between calibration
  • Does not respond to residual chlorine
  • Resistant to detergents in the water
  • Onboard PID controls
  • Onboard data logging and graphing capability
  • Onboard comms such as TCP/IP, Modbus, Profibus and more.

The OzoSense sensors and flow cells are available with different ozone controllers giving you the same great performance with different communication, display, and control options.

The OzoSense Residual Ozone Monitor suffers no interference from other oxidants such as Chlorine. Coupled with its excellent zero and calibration stability it is extremely well suited to the monitoring of the Residual or Dissolved ozone concentration in water in clean or harsh environments.

Pi’s Ozone Monitor is bufferless and reagent free, meaning it has a low total cost of ownership and with maintenance intervals at 3 or even 6 months, the bufferless Ozone Monitor is fast becoming the instrument of choice for the engineer who wants the best ozone monitor at the best price.

Ozone controller

Ozone controller installation in Turkey

Ozone Analyser Water Treatment Applications

The OzoSense dissolved ozone controllers are currently installed on many applications including:

  • Ozone Dosing Control – Ozone controllers
  • Remote Sites
  • Cooling Towers
  • Food Preparation
  • Hospitals
  • Secondary Ozonation
  • Waste Water Ozonation

Anywhere you have a requirement to measure residual ozone is a suitable application for the OzoSense. The OzoSense dissolved ozone controller range is particularly suited to working in sites where reliability and ease of use are most important. The sensor is resistant to the presence of tensides making it suitable for use in many washing applications.


As described in a separate brochure, the OzoSense can come equipped to automatically clean itself at user defined intervals with all the benefits of no operator intervention for 6 months. The Autoflush is particularly useful in food preparation, pulp and paper, and many applications where there is likely to be a build up of solids in the sample.

Multi-Sensor Systems

The whole range of OzoSense Ozone Monitors and Controllers can be fitted with additional sensors such as more ozone sensors, chlorine, pH and many others. Such flexibility can save considerable sums of money when putting together and monitoring or controlling solutions for ozone.

What range of ozone sensors are available?
Pi offers ozone sensors from a range 0.05-0.2, 0.05-0.5, 0.05-2, 0.05-5, 0.05-10, 0-20 mg/l (ppm).

Can I measure ozone in seawater?
When you add ozone to seawater you get bromine. Pi offers a total bromine sensor for this application.

How often do I calibrate my dissolved ozone sensor?
This depends on the application. The online residual ozone sensor has a very low drift so most people calibrate it either once a week or once a month.

How often do I change the online ozone sensor electrolyte?
Every 3-6 months.

Can I measure ozone in the presence of tensides (detergents)?
Yes, the OzoSense is resistant to the effects of tensides.

Can I operate the sensor at an overpressure so I can return the sample to the process?        
Yes and No. The sensor can operate at 1 bar overpressure but the pressure must be constant or the reading will vary. This is usually not enough to put the sample back into a process so most customers use an open flow cell to ensure a constant pressure.

Will changing pH affect the reading?

What is the shelf life of the membranes and electrolyte?
If stored in a cool dry place, two years.

What are the interferences?
There will be a small response to residual chlorine  (<2%) and also to chlorine dioxide (<7%).

What are the materials of construction?
PVC, stainless steel and perspex.

What is the Temperature range of the sensor?
>3 °C – < 50 °C.

Why is there no zero adjustment?
The sensor operates at a positive voltage all of the time so any drift on the zero is negligible compared to the positive operating voltage so no zero is necessary.

What will happen if the temperature varies?
Nothing! The sensor has a thermistor that measures the temperature and does an automatic compensation.

What should I use to calibrate the sensor?
Use a handheld meter. These are available from a variety of suppliers and nearly all of them utilize colorimetric DPD to determine the ozone concentration in the sample.

What do I have to think about when I am taking a sample to do a DPD test?
Firstly take the sample from right at the instrument. Secondly don’t take the sample when the concentration is varying quickly, and thirdly use a good quality handheld and follow the instructions carefully.

I have tried to calibrate and the analyzer says that the sample wasn’t stable?
During calibration the analyzer looks at the stability (rate of change) of the signal from the probe and if it varies by more than 10% over the countdown then the analyzer prevents calibration to avoid the calibration routine introducing errors.

What is Ozone?
Ozone is an allotrope of Oxygen having the chemical formula O3. It is three Oxygens joined together. It decays to O2.

Why is Ozone used to disinfect water?
Dissolved ozone is a powerful oxidant and can therefore be used to disinfect water. Specifically it can:

  • React with and remove manganese
  • Destroy some pathogens resistant to chlorine such as Giardia and Cryptosporidia.

Why Is Ozone favored for some applications?
Ozone disinfects and leaves no taste or odor. In addition it completely breaks down urea so doesn’t form organochlorine or combined chlorine products.

If you have any other questions relating to the online measurement and control of dissolved ozone, please don’t hesitate to contact us.