How to Use the Salinity Meter
- Dip the probe into the liquid to be measured.
- Press the ON button.
- Stir the meter to get rid of bubbles, until the display becomes stable.
- Read the figure from the display, which is salinity in parts per hundred.
- Rinse the meter with distilled water and blot dry after each use.
Sampling and Testing Tips for Farmers testing Bore Water or Dam Water
Measuring water salinity will indicate if it is safe to use the water for irrigation. You may be limiting plant growth and importing salts onto your farm without realising the cause. Measuring groundwater salinity will show how salty your surface soil is likely to become if the watertable
rises close to the surface.
You should regularly test groundwater samples from bores and piezometers; and surface water from drains, creeks, dams, bay water, seeps and discharge sites.
The digital salinity meter is accurate enough to determine the salinity of water for most farm purposes. Alternatively, a sample can be sent to a laboratory for testing and analysis if the water
will be used for household purposes or livestock. Note that although a water salinity test is easy,
testing a soil sample is a more reliable assessment of the amount of salt actually affecting crops and pastures. Surface water tests provide a reading that is only accurate at the time of testing. The salinity can change sharply in a short space of time, so test water salinity regularly. For example, evaporation can concentrate salts, and rainfall can dilute them. Also, slugs of particularly salty water can flow down rivers and creeks. Groundwater salinity tends to remain more constant in the short term.
- Make sure that you mix the water thoroughly before taking a sample to test.
- Rinse the sample container with the sample water before collection.
- When sampling from a dam: collect a sample from any channel entry points, and at several other locations around the dam. Avoid collecting muddy sediment.
- When sampling from a channel, creek or river: try to collect sample from the middle of the streamflow and near your pump intake.
- When sampling from a bore: collect a sample from a turbulent area near the outlet pipe, after pumping for at least 30 minutes.
- When sampling from a testwell: try to bail out as much of the water already in the testwell, and allow fresh groundwater to flow in (because some water in the testwell will have evaporated, concentrating the salts in the remaining water and giving an artificially high reading).
- The salinity meter should read zero when held in the air. If it doesn’t, the meter needs to be calibrated (refer to the instructions thst come with the meter).
- If the salinity is out of the range of the meter, samples can be diluted by a fixed amount. For example, mixing a sample with an equal volume of distilled water will halve the total salinity. Double the reading to find the true salinity of the sample.