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Types of pH sensors: Exploring methods to measure liquid pH levels

The types of pH sensors differ based on any desired application. Generally, they detect acids in any liquid solution. So consider the optimal product, specifications, and features while searching for pH sensors for suitable environments. Otherwise, it performs incorrectly, providing inaccurate measurements. Continue reading to understand these liquid-monitoring devices!

What is a ph sensor?

Example of a pH sensor.

Example of a pH sensor.

Generally, a pH sensor precisely detects acid and alkali in various solutions. With proper maintenance, these devices help a product meet essential safety and quality regulations for relevant applications, including wastewater.

The pH levels a sensor can measure.

The pH levels a sensor can measure.

Typically, pH level values range between 0-14, with seven representing a neutral level. For instance, values exceeding seven mean stronger alkalinity. Meanwhile, anything under 7 equals higher acidity. Companies utilize pH sensors for environmental or manufacturing applications.

Types of pH Sensors

Various pH sensors exist on the market today. 

Various pH sensors exist on the market today. 

Different environments rely on a specific pH sensor for proper measurements, simplifying the process task. We listed the popular liquid monitoring device types below:

Types of pH sensors: PTFE pH sensor

This sensor type measures the pH of a solution that includes organic compounds. Generally, it features a low-impedance glass film, making it corrosion-resistant, acid-resistant, and alkali-resistant. Also, the sensor comes with a glass bulb safeguard, keeping it intact against potential breakage.

Types of pH sensors: Combination pH sensor:

The combination pH sensor contains a measurement and reference electrode. The measurement electrode determines whether the pH level has changed. Meanwhile, the reference electrode ensures the signal remains steady during pH measurements.

Laboratory pH sensor:

Types of pH sensors:  Measuring the pH of a liquid in a laboratory.

Measuring the pH of a liquid in a laboratory.

The lab pH sensor, designed for pool monitoring, research, and other applications,  utilizes combination sensor technology. Three options exist for this type: basic (pH1000), advanced (pH2000), and research (pH3000). Plus, you can customize the cables, sensor fills, and junctions for any intended application, making these sensors versatile!

Differential pH sensor:

Differential sensors feature a metal ground electrode and a reference and measurement electrode. These generally stop reference fouling from occurring, so contaminations won’t affect the overall pH measurements. Differential sensors have applications in harsh wastewater and industrial environments.

Process pH sensor

Similarly, process pH sensors also feature combination sensor technology and monitor water quality levels. They contain process connections suitable for consistent monitoring. Brands utilize this sensor build for reference, measurement, and combination electrode manufacturing.

Maintaining the pH sensor:

Types of pH sensors:  Properly maintaining a pH sensor ensures that it works correctly. 

Properly maintaining a pH sensor ensures that it works correctly. 

A well-maintained pH sensor ensures everything runs perfectly. Otherwise, the electrode experiences problems from oil buildup, reference contact blockage, and pH bulb issues. Reference poisoning also occurs, causing electrode failure.

Follow these guidelines for optimal protection of your pH sensor. Submerge the electrode in dishwashing liquid and warm water for oil buildup removal. Afterward, dip the electrode in distilled water and calibrate it with pH 4 or 7 buffers. You must replace the electrode if calibration attempts fail. Also, a non-porous electrode helps prevent reference poisoning and reference junction fouling. Placing a bulb guard over the pH bulb protects it against potential damage or breaks.

How does the pH sensor work?

Putting the pH sensor probe into a solution causes hydrogen ions to surround the bulb. This generates a voltage that the bulb’s silver wire obtains. Then, the pH meter converts that voltage into a value, providing measurements based on the potential difference between the reference and measuring electrode. 

Higher acidity leads to higher hydrogen ion concentration that boosts voltage levels. Thus, the pH value, shown on the meter, also drops. If the sensor detects higher alkalinity, then the hydrogen ion concentration decreases. This results in a voltage drop, leading to a higher pH value.

Application of pH Sensors

Types of pH sensors:  You can utilize a pH sensor in many applications. 

You can utilize a pH sensor in many applications. 

You will find pH sensors widely utilized in industrial settings, among others. A few examples include:

  • Manufacturing
  • Agriculture
  • Wine or beer brewing
  • Healthcare and clinical
  • Swimming pools
  • Cheesemaking

Types of pH sensors: Pros and Cons of pH sensors

Generally, pH sensors offer varying advantages and disadvantages. We listed a few below:


  • Quickly provides highly accurate readings.
  • Calibrated with pH 04, pH 07, or pH 9.20 buffer solution
  • Portable
  •  Wide range of applications


  • Costly
  • Requires frequent calibration 
  • It can easily break due to weak glass electrodes
  • Electrode membrane deposits may interfere with processes 


You can monitor continuously through pH sensors, which detect strong acids in solutions. These are also incredibly practical in heavily polluted regions, determining when treatment must start. Thus, you will commonly see them deployed in the industrial, agriculture, sewage, and aquaculture fields.

Do you have any inquiries regarding pH sensors? Feel free to contact us!

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Emma Lu
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