What Does The pH Level in Your Pool Mean and How to Test It

In addition to alkalinity and calcium hardness, the pH level is an important factor for the water balance in your pool. But which methods are suitable for measuring the pH level, and how can the pH level be lowered and raised?

An electronic device to test the pH level in the pool is best, but measurement with test strips or tablets is sufficient for beginners. The pH level should be between 7.2 and 7.6. A pH minus is used to lower the pH level, and to increase the value, a pH plus is needed.

I will explain how the pH level in the pool or whirlpool is tested, which pH level should be adhered to and how to optimize the water with simple pool chemistry.

What does the pH level in the pool mean?

The pH level measures how acidic, neutral, or basic (alkaline) the water in the pool is.

As pool owners, we aim for a neutral pH level between 7.2 – 7.6.

But what does the pool pH level mean exactly?

The effectiveness of the pool chemistry (chlorine, bromine, etc.) is influenced by the pH level.

This means: Depending on the current pH level, the disinfection effect in the pool increases or decreases. This leads to excessive use of pool chemicals, increased costs, and clouding of the pool water.

That is why the pH level is one of the essential parameters in pool maintenance, along with disinfectants.

The pH level interacts with the calcium hardness and the alkalinity in the pool, all three of which are decisive for the water balance.

A deviation leads to various problems. In the worst case, damage to the pool and pool equipment occurs if the pH level is not between 7.2 to 7.6.

But what are the exact consequences if the pH level is not optimal?

Test the pH level in your pool

The pH level must be checked regularly and, if necessary, optimized so that the pool water remains crystal clear.

But how often should the pH be checked per week?

A pH level test in the pool should be done once a week. If the pool is used frequently and the number of bathers increases, I recommend measuring the pH level twice a week.

In a pool, the pH should be between 7.2 to 7.6 for optimal water balance.

The following pH level color table shows the optimal pH level.

pool ph level

And what method can be used to measure the pH level in pool water?

As a private pool owner, you choose between test strips, tablets, or electronic water test devices to test the pH level.

In the following chapters, I explain the individual differences and tell you which method I find the best for measuring the pH level in the pool.

#1 Digital pool water meters for pH

The measurement of the pool water with an electronic pool water meter is preferable to all other methods.

This is because the electronic measurement determines the total pH level.

The probes in the device can determine the pH level precisely.

This is practical, as this method allows the pH plus or pH minus to be precisely dosed.

The operation of such devices is simple, but electronic water testers need to be calibrated regularly – read the instruction manual.

An electronic measuring device is not cheap, but it is much more sustainable than test strips.

Invest in such a device once and benefit from precise data on water treatment.

I guarantee you: Pool maintenance will be a lot easier with an E-Tester, and you won’t have to spend the whole day looking for errors in your pool.

#2 Tablets and liquid indicators to test the pH level

The pH level test with tablets or liquid indicators is called the colorimetric method.

For this purpose, a certain amount of the pool water is filled into small glass tubes. Then an indicator in the form of a tablet or a drop is added.

With the enclosed color scale, the pH level can be read off from the discoloration of the water. But here are measurement errors to be expected.

#3 Determine the pH level with measuring strips for the pool

When testing the pH level with test strips, you can only measure between a pH level of 6.0 to 8.2.

The test strips are dipped into the pool water and then briefly air-dried. The measured pH level can be adjusted using the color scale (see packaging).

I have to mention here: Measurement errors can often occur with this measurement method.

It is difficult to call this method an actual measurement. A rough estimate of the pH level describes this technique better.

Therefore, the measuring strips for private swimming pools and whirlpools are only suitable for occasional measurements.

If the pH level fluctuates frequently, I recommend measuring with an electronic tester. The acids for the correction can only be optimally dosed with an exact pH level.

#4 Titrimetric measuring method

Another measuring method – which I would like to mention briefly – is the titrimetric method.

In the case of the titrimetric method, as in the case of the colorimetric method, a little water is first filled in, and an indicator is added.

Then a titer (a drop) is used as a suitable indicator.

The measurement result can be determined based on the added drops.

#5 Photometric method of measuring the pool pH level

The photometric method works a little more complicated – than the colorimetric method – and is conditionally recommended for newbies.

Here a defined beam of light shines through a colored water sample. After that, the measuring device measures the differences in concentration.

The pH level is then displayed digitally.

Photometric measuring devices are practical, but they are one of the most expensive.

The remarkable thing about the photometric measuring method is that chlorine and almost every other parameter can be precisely determined, in addition to the pH level.

Problems due to incorrectly measured pool pH level

Is the pH level crucial for the pool maintenance, and does it inevitably lead to problems in the pool if it is not tested regularly and optimized?

Even a tiny deviation in the pH level leads to various problems in the pool.

I have listed the different pH levels ​​and show in this table which problems can be expected if the pH level in the pool or whirlpool is not adjusted.

pH level Status Symptoms
below 7,0 Acid Metal parts rust, joints are loosened, disinfectants use up faster, burning eyes
over 7,6 Basic Cloudiness in the pool, milky pool water, the oxidizing power of chlorine decreases
above 8,0 Basic Lime precipitation and lime on the walls

The table clearly shows that a pH level that is too low leads to acidic (corrosive) water. The acidic water rusts metal parts and loosens the joints.

Rusting components lead to high iron content in the pool water, creating stains in the pool.

But the damaged joints are also ideal nesting places for the dangerous black algae and other organic contaminants.

The oxidizing power of chlorine and other disinfectants increases at a pH level below 7. Still, the chlorine consumption also increases by 50% – so you need more pool chemicals for water treatment (extra costs).

A high pH level above 7.6 is also problematic.

Limescale on the pool walls, misted filter sand, and milky pool water are the symptoms when the pH is above the ideal level.

Furthermore, the disinfecting effect of chlorine decreases, and the pool water turns green.

In both cases – too low and too high pH levels – there are expensive repair and purchase costs in the pool.

The reason why the pH level in your pool rises and falls

But what are the main reasons why the pH level rises and falls?

The pH level in the pool increases by:

  • The water circulation through the pool pump.
  • High pool water temperatures.
  • An oversaturation of organic contaminants in the pool.
  • Degassing processes through countercurrent systems and running filter systems.

You can read about my exact procedure on lowering the pH in the pool in my blog article. Just click on the link.

The pH level in the pool drops due to:

  • Urea contamination.
  • Excessive use of cyanuric acid in the pool.
  • Acid rain causes the pH level in the pool to drop.

I also wrote an article with detailed instructions on how to raise the pH level in the pool.

I have already explained to you above in the text how you should test the pH level in your pool and which methods work best.

Common questions about pool pH level

Some readers have other questions about the pool pH level that I would like to answer in this area.

How often should you measure the pH in the pool?

The pH level is one of the parameters ​​in the pool that should be checked regularly.

I recommend measuring the pH level over the entire season 3 to 4 times per week and, if necessary, correcting it.

You can see how this works here in the video.

What is the ideal pH level in a saltwater pool?

Seawater has a natural pH of 7.8 to 8.2.

Opinions differ when it comes to the optimal pH level for private saltwater pools.

I recommend in saltwater pools a pH between 7.4 to 7.6.

Why does the pH fluctuate continuously?

If you notice strong fluctuations up and down when measuring the pH level, then it is very likely that the alkalinity (acid capacity) has fallen below 80 ppm.

In this case, you have to optimize first the alkalinity and then the pH level in your pool.

Can you automatically regulate the pH level in the pool?

The pH level can be regulated with an automatic pH metering system.

The system is connected to a power source and the pool’s water circuit.

But be careful: The pH agent must be available in liquid form as a supply source. In addition, the systems are relatively expensive and have certain risks. Source.

What is the optimal pH level in a hot tub?

It doesn’t matter whether you correct the water in the pool or the hot tub.

That is why the same pH level between 7.2 and 7.6 is ideal in the whirlpool. Anything below or above the optimum leads to milky water.

Do you have any further questions about the pH level and the measuring method? Contact me at @contactswimfool on Twitter, Pinterest, Facebook, and Co.

I hope you enjoy swimming!

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Hi. I'm Max Berg. I've been in the pool industry since 2015 and have always felt drawn to water. I'm the author behind swimfool.com, where I share my years of experience in pool maintenance and give helpful tips on keeping a swimming pool or hot tub clean. My tips reduce the costs of water treatment and protect the environment.

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