Conductivity (EC)

Electrical conductivity (EC) describes the ability of a liquid to conduct electrical current. It is one of the most important measured variables in water analysis and provides information about the concentration of dissolved ions in the water. These ions include sodium, potassium, calcium, magnesium and chlorides, for example.

The more dissolved salts and minerals there are in the water, the higher the electrical conductivity usually is. EC measurement is therefore often used to assess water quality and to monitor processes in industry, agriculture, laboratories and water treatment.

What is electrical conductivity?

Electrical conductivity is usually referred to as the EC value. It describes how well a solution can conduct electric current.

Pure distilled water only has a very low conductivity. Only dissolved ions increase the ability of water to transport electricity. Conductivity is therefore an important indicator of the concentration of dissolved substances in a liquid.

Why is EC measurement important?

The conductivity measurement enables a quick assessment of the water quality and the concentration of dissolved substances. Changes in the EC value can indicate changes in the water composition, impurities or fluctuations in the nutrient content.

The measurement of electrical conductivity is used, among other things, for

• Drinking water analyses
• Water treatment
• Aquaristics and fish farming
• Hydroponics and plant breeding
• Agriculture
• Environmental monitoring
• Industrial process control
• Laboratory applications

The EC value is often used to monitor the concentration of available nutrients in the water, particularly in plant cultivation.

How is conductivity measured?

Special conductivity meters are used for precise measurements. These determine the electrical conductivity of a liquid using a conductivity electrode or probe.

Modern EC measuring devices record the measured values within a few seconds and often have automatic temperature compensation. This means that reliable measurement results can be achieved even with changing temperatures.

Conductivity, TDS and salinity: What’s the difference?

Electrical conductivity is closely related to other water parameters such as TDS (Total Dissolved Solids) and salinity.

• Conductivity (EC) measures the ability of a solution to conduct electrical current.
• TDS describes the estimated total amount of dissolved substances.
• Salt content (salinity) indicates the concentration of dissolved salts.

Many modern measuring devices can therefore determine and display several of these parameters simultaneously.

What factors influence conductivity?

The conductivity of a liquid is influenced by various factors:

• Concentration of dissolved ions
• Salt and mineral content
• Sample temperature
• Chemical composition
• Impurities and additives

As the temperature has a direct influence on the measured value, professional EC measuring devices often have automatic temperature compensation.

Typical areas of application for conductivity measurement

Water treatment

Conductivity is used to monitor drinking water, process water and purified water. Changes can indicate fluctuations in water quality.

Agriculture and hydroponics

The EC value helps to monitor the nutrient concentration in irrigation systems and nutrient solutions.

Aquaristics

Regular EC measurement supports the control of stable water conditions for fish and plants.

Industry and laboratory

In industrial processes and laboratory applications, conductivity is often used for quality control and process monitoring.

Conductivity meters from Apera Instruments

Apera Instruments offers a wide range of EC measuring devices for professional and private applications. The range includes compact Pocket Testers, portable measuring systems and high-precision laboratory devices for demanding analyses.

Thanks to modern sensor technology, automatic temperature compensation and high measuring accuracy, Apera conductivity meters enable reliable monitoring of water quality in a wide range of applications.