How Often Should You Test Pool Water? (Not What You Think)



Wondering how often you should test your pool water?

As a new pool owner, it’s difficult to tell whether you should test your pool chemistry every day, every week, or every other week – especially when everyone seems to have a different answer.

Today, we’re going to break down this age-old question by tackling some of the more conventional wisdom around pool testing frequency.

Quick answer: Every pool is different; you need to learn how your chemistry fluctuates before you nail down the optimal testing frequency. With that being said, most pool owners test the basic markers at least twice per week.

How Well Do You Know Your Pool? (Best Answer)

This is the question that really determines how often you should test your pool water.

If you’re a new pool owner (or if your pool is new), it will take some time to learn how your water changes over time, and, more importantly, how quickly those changes happen.

In particular, pH and free chlorine are the key variables when it comes to maintaining proper sanitation, so these will require more frequent checks.

But here’s the thing:

Some pools see dramatic pH changes in just a day or two, while others go weeks with virtually no changes. Similarly, some pools chew through chlorine like it’s going out of business, while others last days without requiring a top-up.

Once you have a grasp of the “personality” of your pool water, you can adjust your testing schedule accordingly. (After all, there’s little point in testing every day when your water typically doesn’t budge for days at a time.)

Until then, you should be testing your pool water at least twice weekly, but ideally every day to begin with.

How Often You Should Test Your Pool Water? (Blanket Answer)

Perhaps you’re looking for a more generalized answer and one that you can use as a basis for your pool maintenance schedule.

Below is our recommend test frequency for each parameter:

Test pH and Free Chlorine Twice-Weekly

Your pH level needs to sit between 7.2-7.8 to create the ideal conditions for balanced water, proper sanitation, and swimmer comfort.

Free chlorine or free bromine should be between 2-4 parts per million, and 3-5 ppm, respectively. This will ensure there’s enough active sanitizer in the water, protecting you against contaminants such as insects or algae.

Both pH and free chlorine should be measured at least twice per week and can be tested using a pool testing strip or liquid test kit.

Note: The standard 4 or 5-way strips often don’t test for bromine, so you’ll need to use the 7-way test strips if you have a bromine pool.

Test Total Alkalinity Weekly

Your total alkalinity should be between 80-120 parts per million in order to buffer your pH level and keep it stable.

Alkalinity and pH are closely related, so maintaining your pH level will often keep your total alkalinity steady. As such, if your pH level is out of whack, you can also expect some significant changes in your alkalinity.

Total alkalinity can be tested using either a test strip or liquid drop kit.

Test Calcium and Stabilizer, and Metals Monthly

Your calcium level determines the hardness. It should be between 200 and 400 parts per million to avoid being under or over-saturated, which may lead to corrosive water or calcium scaling.

Your chlorine stabilizer (cyanuric acid) should be between 30 and 50 parts per million to protect your chlorine from sunlight and help regulate chlorine consumption in your pool.

Both calcium hardness and cyanuric acid can be tested using standard test strips or using liquid reagents.

Test Metals Every One to Three Months

Metal content such as iron and copper should be as close to zero as possible, as they offer no benefits to your water.

For both iron and copper, anything 0.3 parts per million may result in metal stained surfaces or murky brown/cloudy water after adding chlorine, and these side effects can be difficult to rectify.

Most pool test kits won’t measure metal content in your water, so this is one of the few tests that are best done at your local pool store.

Test Salinity Monthly (Saltwater Pools)

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If you have a saltwater pool, you’ll also need to test for salinity (salt level).

Your salinity level should be between 2700 and 3400 parts per million in order to have sufficient salt available to your saltwater generator and ensure its ability to produce enough chlorine.

Strips that test for multiple parameters likely won’t include salinity, so you may need to purchase a separate strip for this, or simply use a compatible liquid test kit.

The Type of Test Kit You Use Matters

We’ve briefly touched on test strips and liquid test kits above, but it’s important to differentiate between the two.

To be more specific:

  • Test strips are very affordable and easy to use, but they simply aren’t as accurate as liquid test kits – especially when it comes to reading the pH level, which you’ll be doing often.
  • Liquid drop kits are more expensive and a little more time-consuming to use, but they’re easily the gold standard in accuracy for at-home pool testing. They also include a wider range of parameters, such as combined chlorine.

While some pool owners prefer to pick a team, the best approach is often a hybrid of the two testing methods.

For example, you could leverage the ease-of-use of test strips for more frequent testing, while saving the more labor-intensive drop test for more reliable water evaluation at the end of every week.

Listen to Your Pool

Every pool is different, so you’ll need to figure out the right testing frequency for your pool by starting at a higher frequency and slowly working back.

So while you may need to start out testing your pool water as often as every day, you’ll soon be able to reduce that to twice-weekly, weekly, or even less depending on the overall stability of your pool chemistry.

Of course, there are exceptions to following a strict schedule. Whether it’s a freak storm or a “little accident”, always be ready with a test kit in hand.

Categories: Pool Care, Pool Chemistry