Equipment :
50ml beaker (if using green meter)
500𝝻S/cm (Low) OR 12,880µS/cm (High) Calibration Standard*
500ml water sample
Distilled water
Green OR Grey Electrical Conductivity Meter
Safety glasses
Specimen container
(And you can skip step 2.3.2.1 and 2.3.2.2 and go straight to 2.3.3.1 or 2.3.3.2).
Check your EC meter with the standard every month.
For all sites except B8 and B8.1 - Use 500µS/cm calibration solution.
For sites B8 and B8.1 - You may need to use both the 500µS/cm and 12,880µS/cm solutions depending on whether you are measuring on an incoming or outgoing tide.
Tip : Some volunteers prefer to complete this test the night before testing.
1. Pour enough 500µS/cm or 12,880µS/cm (see Important section above) calibration solution into a clean beaker to cover probes.
Pour to a depth of approx. 3cm or 30mL in your small beaker.
2. Take bottom cap off the EC meter and turn on.
(By pressing ‘on/off’ button).
3. Dip the probes into the calibration solution and swirl the container, meter and solution.
Important - Immerse only the probes of the meter in the water.
(The whole meter is NOT waterproof).
4. Wait several seconds until the number stabilises.
5. Discard the calibration solution into the liquid waste container.
6a) If meter does not read 500µS or 12,880µS (or within +-2 µS/cm), you need to calibrate your meter.
Calibrate Grey EC Meter - go to Part 2.3.2.1
Calibrate Green EC Meter - go to Part 2.3.2.2
6b) If the meter reads 500µS or 12,880µS (or within +-2 µS/cm), you do not need to calibrate your meter and can go straight to the EC test.
Grey EC Meter Test- go to Part 2.3.3.1
Green EC Meter Test - go to Part 2.3.3.2
Packup
1. EC meter MUST be washed with distilled water, not rain or tap water!
2. Keep the meter in a cool dry place - never leave your meter in the car as it can overheat and destroy the internal thermometer.
3. Replace batteries regularly as flat batteries will produce inaccurate results.
Maintenance : every 6 months
Soak the EC meter probes with methylated spirits for 1-2 minutes then rinse with distilled water and calibrate as usual.
Reason: At higher salinity sites, sometimes the EC meter can attract salt onto the probes which can affect results if the probes aren't rinsed really well each time. So, it's a good habit to get into, as the methylated spirits helps to remove any excess salt off the probes.
Electrical Conductivity (EC) is the measure of the ability of water to conduct an electric current and depends upon the number of ions or charged particles in the water. EC is an indirect method of measuring salinity and includes the measurements of all salts and organic acids. Many species can only survive in a very narrow range of salt concentration.
The unit of measurement for electrical conductivity is expressed in either micro Siemens per centimetre (µS/cm) or milli Siemens per centimetre (mS/cm).
