When I was a kid, I remember seeing the pool guy test my parent's pool every week.  He would walk onto the job, pull out a fancy-looking device, and drip the water into tubes of colorful water.  He was so methodical, serious, and precise that I thought he must possess a chemistry degree (or at least a certification in pool water testing!)

Fast forward thirty years: I now maintain my own pool.  And pool water testing is far, far simpler than I had been led to believe.

In fact, it's so simple it takes less than 2 minutes per week.  And using the method I'm about to describe, my pool water has never looked better.

How to Test Your Pool Water Using Test Strips

First, you'll need to get your hands on some test strips.  LaMotte Insta-Test 6 Plus strips are simple, convenient, and our favorite ones to use.

Once you have your test strips, pick a time to test your water and circulate your pool water for at least one hour.  This will stir up your water and provides for a more accurate reading.

Also, make sure not to add any chemicals prior to pool water testing.  If you do, your result won't be as accurate.

OK, now that your water is churned, there are two procedures you can follow: Surface scan or Deep Water scan.

I'll explain both pool water testing methods here:

Surface Scan (Quicker, Potentially Less Accurate)

Pick a spot where you will take your water sample.  Make sure it isn't close to a return jet, a skimmer opening, or a floating chemical dispenser.  Whatever spot you choose should be where you perform all future tests as well.

1. Remove a test strip from the bottle and securely fasten the lid.
2. Hold the test strip, without touching the pads, and immerse it in the water for 2 seconds.
3. Remove the strip with the pads facing up.
4. Shake once to remove excess water.
5. Compare your test strip result to the label on the container.

Deep Water Scan (Slower, Potentially More Accurate)

1. Pick a spot where you will take your water sample.  Make sure it isn't close to a return jet, a skimmer opening, or a floating chemical dispenser.  Whatever spot you choose should be where you perform all future tests as well.
2. Take an ordinary plastic cup (or bottle) and submerge it in the water with the cup opening facing the bottom of the pool.
3. Once you are 12 to 18 inches deep (usually, elbow level), turn the cup right side up so that it fills with water.
4. Pull cup straight up out of the water and set it to the side.
5. Remove a test strip from the bottle and securely fasten the lid.
6. Hold the test strip, without touching the pads, and immerse it in your cup for 2 seconds.
7. Remove the strip with the pads facing up.
8. Shake once to remove excess water.
9. Compare your test strip result to the label on the container.

That's all there is to it!

Personally, I use both types of scans in my pool maintenance routine.  When I wish to check the water in between my weekly maintenance, I do a quick Surface scan.  However, when it's the weekend and I'm putting my 15 - 30 minutes into the pool, I do a Deep Water scan.

Because the Surface scan is less involved, it's quicker.  But the Deep Water scan is more accurate and it's important to do frequently.  You see, gas from certain chemicals will rise to the top of your pool water, and potentially interfere with a surface reading.  Also, if you recently added water to your pool (or had heavy rainfall), it may not have mixed properly, leading to a bad reading.

How to Interpret Test Strip Results

Whether you do a Surface scan or a Deep Water scan, it is important to read your results immediately.  To do this:

1. Hold your test strip up against the bottle.
2. Compare the colors on the strip against the colors on the bottle.
3. Note where your results are in the "OK" range, and where corrective action is needed.
4. Take corrective action by adding the appropriate chemicals to your pool. (See Pool Chemistry for Dummies on how to take corrective action)

Frequently Asked Questions

Now, I will address some common questions we receive about test strips.

What test strip should I buy?

At Poolhop, we prefer a more well-rounded 6-way pool water test strip that measures Free Chlorine, Total Chlorine, Total Alkalinity, pH, Calcium Hardness, and Cyanuric Acid like the LaMotte Insta-Test 6 Plus strips.  At the very minimum, you will need a 3-way test strip that measures Free Chlorine, pH, and Total Alkalinity.

How often should I test my pool water?

We recommend testing your pool water weekly during the swim season, at the very least.  That is only half the battle however.  You need to know what the test levels mean in terms of pool chemical application.  That is why we built a free online pool chemical calculator that tells you which chemicals to add based on your test levels. Any time you are making pool chemical adjustments, you should test daily until the pool water is balanced.

Where should I store my test strips?

Ideally, you should store your test strips indoors to maintain freshness and accuracy.  If this is too inconvenient and you choose to store them outside, make sure they are out of the elements, in a cool, dry location.

When should I not use test strips?

Over the years, test strips have become much more reliable.  They provide a quick and easy way to ballpark the basics.  However, if one or more of your results repeatedly shows outside the "OK" range, you should consider a different test.  Another reason not to use test strips is that they have reached their expiration date.  In this case, discard and replace them before performing a pool water test.

What other methods can I use to test my pool water?

The easiest method is to take your water down to your local pool store.  First, take a pool water sample by following the Deep Water scan procedure shown above.  Make sure to use a bottle with a cap so your water doesn't spill in transit.  Another option is for you to learn how to test your own water (see next question).

Of course, I would be remiss by not pointing out that Poolhop provides free online tools to test your pool water and produce a complete DIY pool maintenance plan for the entire year.

Someone told me that store-based pool water testing isn't accurate as it's designed to sell more products...should they be believed?

I personally have not experienced this, but I know that some in the pool industry believe this.  If you are skeptical, the best thing you could do is buy your own home test kit.  And then watch a video or two to learn how to use it.

Conclusion

Thank you for stopping by.  We hope you found some value in this article on pool water testing.  Please feel free to leave a comment or a question below!