What Is an EC Meter?

EC meters are relatively simple tools that perform sophisticated measurements resulting in a wealth of information about the nutrient content of soils and liquid samples.

This article focuses attention on answering the question, “What is an EC meter?” To do this, we investigate:

• “What is EC?”
• “Why measure EC?”; and
• Provide some examples of EC measurement applications along with some example products.

What is EC?

EC stands for Electrical Conductivity (often abbreviated to simply Conductivity). Electrical Conductivity is the measure of the concentration of ions present within a sample. It is calculated by the ability of a substance to transmit an electrical current over a defined area.

Distilled water is a poor conductor of electricity - it contains no ions. Water with salts and other dissolved inorganic chemicals will have a higher ionic concentration, and therefore, higher conductivity level.

Why Measure EC?

Conductivity is a valuable and commonly measured water quality parameter. Incidentally, Siemens (S) (I.e. Milli Siemens per centimetre mS/cm or Micro Siemens per cm μS/cm) is the unit used when measuring electrical Conductivity.

It’s important to know that there is a strong correlation between Conductivity, TDS and salinity. And because Conductivity is easier to measure than TDS and salinity, many devices first determine the Conductivity of a sample then employ an algorithm to estimate salinity and TDS concentrations.

EC Meter Applications

The vital information yielded by EC Meters can then be applied in a host of agricultural, civic and commercial applications such as: 

• Cropping and pastoral: Electrical conductivity measurements can indicate the salinity, dissolved nutrient, and dissolved solid levels present in the soil. This information can help you make good decisions about irrigation and fertilising.
• Aquariums and aquaculture: A conductivity meter makes it straightforward to monitor water salinity and levels of total dissolved solids. You can convert conductivity readings to total dissolved solids (TDS) or salinity concentrations manually or use a conductivity meter that has this feature built-in. These readings can then be used to maintain a healthy environment for your farmed species.
• Water Treatment: Conductivity data plays an increasingly significant role in managing environmental water quality. Keeping conductivity and salinity measurements within the acceptable ranges is key to maintaining healthy and sustainable ecosystems in our oceans and waterways, particularly where wastewater is discharged.
• Boiler Maintenance: Feedwater within boilers contains impurities, and these can eventually cause issues. Any build-up of contaminants will impact the efficiency and safety of the boiler. A conductivity meter enables you to monitor boiler water impurity levels and warn about the likelihood of boiler blowdown.
• Salt Pool Maintenance: A conductivity meter can help you check your swimming pool or spa’s chemical balance. A conductivity meter (with an automatic salt conversion function or converting the conductivity results manually) will indicate when to perform corrective actions to ensure your pool water is safe.

Examples of EC Meters

Check out the cross-section of conductivity meters (below) that your Instrument Choice team has assembled – they represent the variety of instruments available in Instrument Choice’s online store.

EC20 Value Pocket Conductivity Tester Kit Product code: IC-EC20 At a glance: The IC-EC20 offers outstanding value and is well suited for most Conductivity measuring tasks. This reliable meter provides two points of calibration, a broad measuring range, is IP67 rated and floats on water – so there’s no need to worry about accidental drops into a pool or creek!   Great for: Home and professional EC measuring tasks such as: Swimming pools and spas Water treatment; and Tap and drink water analysis.   Specifications: Measures: Conductivity and Temperature Range: Conductivity: 0 to 200.0 uS/cm, 0 to 2000 uS/cm, 0 to 20.00 mS/cm Temperature: 0 to 50°C Resolution Conductivity: 0.1/1 uS/cm, 0.01 mS/cm Temperature: 0.1°C Accuracy: Conductivity: ± 1 % FS. Temperature: ±0.5°C Calibration: Conductivity automatic 1 to 2 points.

Direct Soil EC/temp Tester Product code: IC-HI98331   At a glance: The IC-HI98331 Soil Test Direct Soil EC Tester is a robust, dependable pocket-sized soil conductivity tester that offers rapid and accurate readings using a single button operation.   The IC-HI98331’s stainless steel penetration probe is specially designed to withstand direct soil measurement.   Great for: Direct soil EC and temperature measurement in environments like: Home gardens Schools; and Various agricultural applications.   Specifications Measures: Conductivity and Temperature Range: Conductivity: 0 to 4000 uS/cm; 0.00 to 4.00 mS/cm (dS/m) Temperature: 0.0 to 50.0°C Resolution Conductivity: 1 uS/cm; 0.01 mS/cm (dS/m) Temperature: 0.1°C Accuracy: Conductivity: ± 50 uS/cm (0 to 2000 uS/cm), ± 300 uS/cm (2000 to 4000 uS/cm); ± 0.05 mS/cm (0.00 to 2.00 mS/cm), ± 0.30 mS/cm (2.00 to 4.00 mS/cm) Temperature: ±1°C Calibration: EC/TDS Calibration: Automatic, one-point at 1.41 mS/cm.

Horiba Laquatwin Conductivity Meter Product code: EC-33 At a glance: Pocket-sized and versatile, the EC-33 is recommended for countless conductivity measurement tasks where accuracy and reliability are essential. The EC-33 is IP67 rated, features automatic range, automatic calibration, automatic standard recognition, automatic temperature compensation, and automatic hold of stable measurements – the only thing it doesn’t do is collect your sample!   Great for: Measurement applications such as: Freshwater testing (rain, rivers, lakes, hot springs) Aquariums Boiler maintenance; and Soil testing for improved agriculture.   Specifications Measures: Conductivity, TDS and Temperature Range and Resolution Conductivity: 0 to 199 uS/cm: 1uScm; 200 to 1999 uS/cm: 1uS/cm; 2.00 to 19.99 mS/cm: 0.01 mS/cm; 20.00 to 199.9 mS/cm: 0.1 mS/cm TDS: 0.0 to 99.9 ppm: 0.1 ppm; 100 to 999 ppm: 1 ppm; 1000 to 9990 ppm: 10 ppm Temperature: 0 to 50 C: 0.1°C Accuracy: Conductivity:  (0 to 19.99 mS/cm): ± 2% full scale and (20.0 to 199.9 mS/cm): ± 5% full scale Calibration: Up to 3 conductivity Calibration points.

Starter 3100C Conductivity Bench Meter Product code: IC-ST3100C-F   At a glance: The Starter 3100C Conductivity Bench Meter provides accurate conductivity, salinity and TDS measurements for complex laboratory tasks. Enhanced features include four calibration points, automatic and manual endpoint functions, and one-touch conversion between measurement modes.   Great for: Laboratory use, including high-level experiments and research.   Specifications Measures: Conductivity, TDS, Salinity and Temperature Range Conductivity: 0.0 μS/cm to 199.9 mS/cm TDS: 0.1 mg/l to 199.9 g/l Salinity: 0.00 to 100.0 psu Temperature: 0 °C to 100 °C Resolution ·Conductivity/TDS/Salinity: Automatic range Temperature: 0.1 °C Accuracy Conductivity/TDS/Salinity: ± 0.5 % of the measured value Temperature: ± 0.3 °C Calibration: 4 point calibration.

Conclusion

What is an EC meter? An essential type of instrument for the fast and accurate determination of the nutrient content within a solution. The wide variety of designs suit a host of vital agricultural, environmental management and commercial applications.

Want to browse more examples of conductivity meters? Search the Instrument Choice online store. You’ll find an extensive range of quality, cost-effective units that our scientists have hand-selected.

If you assistance selecting the best conductivity meter for your needs, contact an Instrument Choice Scientist on 1300 737 871 or email [email protected].