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How to test water temperature

What is it? Water temperature impacts many of the other measurables, such as pH, conductivity, and dissolved oxygen. It also changes the water’s density and its ability to support life, absorb gases (like CO₂), and absorb nutrients.

Why is it important? Increases in water temperature can cause some chemicals to become “soluble”: think how quickly salt dissolves in hot water versus cold water. Algae blooms and other vegetation can also grow more quickly in warmer water. This can be problematic for a number of reasons, including the reduced dissolved oxygen that occurs when the blooms decompose.

What does it mean? Different temperatures attract different animal and plant species. Unusually warm water could be an indicator of algae blooms or even pollution discharge.

Learn more

How to test

Using the stream thermometer: Make sure the thermometer is submerged at least 10 cm under the surface of the water. Hold under the water for 5 minutes. You’ll know it’s ready when the temperature has remained the same for at least 30 seconds.

Using Water Rangers' conductivity meter:

  • Turn on the meter by pressing the top button.
  • Dip the meter into the water collected in your sample cup. Do not dunk the whole device in, as the battery is near the top.  Hold in the water for 2 minutes, swishing it around lightly. Continue until both values remain steady for 30 seconds.
  • Tip: If you get a reading of 10 or less, you have not removed the cap or you have taken the sensor out of the water before reading) Read the measurements. We record in µS/cm (microsiemens per centimetre), so check the units. If you get a reading like 1.3, it converts the measure to mS (millisiemens), and you must multiply 1.3 by 1000 and record 1,300 in your form.
  • Don’t forget to turn off the device after use to preserve battery life (top button).
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Open to Collaborate Notice:

Open to Collaborate Notice: Our institution is committed to the development of new modes of collaboration, engagement, and partnership with Indigenous peoples for the care and stewardship of past and future heritage collections. Learn more about Local Context notices.

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