How to Read Pool Water Test Strips

To fully enjoy your backyard pool, you’ll need to ensure your water is fresh, clean and balanced.  To make this happen you’ll need to test the water on a regular basis.  Most public swimming pools are required to test their water every hour.  You won’t need to do it quite that often, but you should try to do it at least once a week – and more often if the pool is getting a lot of use or you’re experiencing heavy rainfalls.  Testing your pool water isn’t particularly difficult, but it requires consistent attention.  In this article, we’ll go over how to read pool water test strips.

Fresh Strips

First of all, it’s important to keep your test strips in a cool and dry place – something which may not be quite so straightforward around a swimming pool that’s used throughout the summer.  Test strips that are out of date, have become moist or have been bleached out by the sun may be difficult to read and give you inaccurate results.

Dip the Strip

When you’re ready to test the water, make sure your pool pump has been running for at least an hour.  Take a single strip and dip it into the water for a few seconds at a depth of about six inches.  With a single shake, remove the excess water and wait for 10 to 20 seconds.  Don’t wait too long to assess the strip as the colour will continue to change over time.  Compare the test strip with the colour chart on the back of the test strip package to ascertain the various levels.


One of the main pool water tests is for chlorine.  Chlorine helps keep your water clear, clean and algae free.  You’ll want your levels to be between 1 and 3 ppm.  If you need to add chlorine, make sure to wear safety goggles, gloves and old clothes as any spills can cause burns and bleaching.  Be careful not to inhale deeply around the chlorine container as the fumes could end up burning your lungs.  Be especially careful on windy days and don’t allow the chlorine to spill onto your deck or it will end up bleached as well.


Your strip will also let you know the pH level of the water.  Your pool will be most comfortable with pH levels between 7.2 and 7.6.  Quite often people think it’s the chlorine levels that cause your eyes to turn red and your skin to be irritated, but it’s actually unbalanced pH levels that cause this.  It’s especially important to test the pool water after heavy rainfall as this could cause a significant drop in pH.  Add the appropriate chemical to raise or lower the pH, wait a couple of hours and test the water again.

Calcium Hardness

Calcium hardness typically needs to be balanced when the pool is opened and will generally maintain appropriate levels throughout the swimming season.  However, if unbalanced it can cause pool liners to become brittle and discoloured making them prone to ripping.  After your pool has been opened, check the calcium hardness levels every month to make sure it remains in balance.

Now that you know everything about water testing,  start dreaming about your perfect backyard pool life, download our free Backyard Escapes guide today.

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