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Many pool owners do not know what pool water pH is all about and the serious consequences of neglecting this part of pool maintenance. If the pool pH is not properly adjusted, other pool chemicals will not be able to work to their full potential and the pool water may become cloudy.

A too high or too low pH value can also have negative consequences for bathers, as well as pool equipment and pool materials.

The basis for good water quality in a swimming pool is a neutral pH.

What is meant by a neutral pH value, how to measure and adjust the pH value in the pool correctly, you will learn in this guide.

With the knowledge from this article, you can quickly identify when something is wrong with your pool pH. We also explain how you can take effective countermeasures.

Presented are different methods to measure the pH of the pool water. From pool water test strips to digital meters, there are a wide variety of methods. We have compared the different methods and present our results here.

We also show you how to adjust the pH value correctly. Either special pool chemicals or home remedies can be used for this purpose. But first, let’s explain the basics of pH.

What is the pH value?

The abbreviation pH stands for the Latin words potentia Hydrogenii or pondus Hydrogenii (potentia=force, pondus=weight, hydrogenium=hydrogen). The pH value tells how strong or weak the acidic or basic effect is in an aqueous solution.

The measurement scale of pH ranges from 1 to 14. In the middle of the range (i.e., at a value of 7), the pool water is neutral. At values below the middle, the water is acidic, and above, alkaline.

For comparison, here are the pH values of a number of liquids you may be familiar with in everyday life:

  • Lemon juice: 2.5
  • Cola: 2.0 to 3.0
  • Beer: 4.5 to 5.0
  • Human skin surface: 5.5
  • Mineral water: 6.0
  • Milk: 6.5
  • Blood: 7.4
  • Soap: 9.0 to 10.0
  • Bleach: 12.6
  • Caustic soda: 13.5 to 14

Theoretically, a pH of 5.5 is ideal for human skin. The problem is that the acidic liquid would harm the metallic substances. It would also cause irritation to the eyes and mucous membranes. (The reason for this is that tear fluid has a higher pH of 7.0 to 7.5.

For swimming pools, a slightly higher pH has become established to avoid these unpleasant consequences of acidic pool water. So:

What is the ideal pH level in the pool?

The ideal pool pH is between 7.0 and 7.4, with the average value of 7.2 representing the optimal pH. At this pH level, eye and mucous membrane irritation will not occur, nor will the pool materials be damaged.

4 Methods to measure the pool pH correctly

Pool water pH can be measured using four different methods. Three of the four methods are analog methods and one is based on digital technology.

Pool water test strips are a simple method for determining pool pH. Using test strips does not provide the most accurate results, but this method is fairly inexpensive and quick to implement.

If you want to have very accurate results when measuring pool pH, you should buy a digital pool water meter. Such a meter only needs to be briefly held in the water and you can read the pH value.

Note: You should test the pool water regularly. At least every week (twice a week in midsummer) you need to examine the pool water and – if necessary – readjust it.

#1 Test Strips

Test strips are not 100% accurate, but are a very convenient way to test pool pH. Especially for inflatable pools that are only used for a few weeks to months, test strips are a good choice.

These test strips convince many pool owners:

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Pool and Spa Test Strips - Quick
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There are different pool water test strips on the market. The difference between them is that the test strips detect the concentration of different agents. Overall, the use of pool test strips is very easy on the wallet.

#2 Test kit with tablets

The pool water test kits with tablets are the analog measurement method we prefer. This is also because the test kits with tablets work accurately on the one hand and are quite inexpensive on the other.

A test kit with tablets and a good price-performance ratio represents this:

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Fire 7 tablet, 7" display, 16 GB,
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In addition to pool pH, other concentrations of chemicals in the pool water (such as algaecide concentration) are also often recorded.

#3 Test kit with liquid

The third analogous method for measuring pool pH is test kits with liquid. The cost of such test kits is also not high.

Friends of test kits with liquid like to grab this product:

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In The Swim 4-Way Liquid Solution
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#4 Digital Pool Water Meter

Digital pool water meters are the most accurate method of determining the pH level in pool water. For owners of in-ground pools as well as larger pools, the electric meters are the right choice.

This digital pool water meter convinces on the full line and offers excellent accurate readings:

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WaterGuru Sense Smart Pool
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Pool water meter manufacturers and popular brands

Measuring and properly adjusting the pool chemistry of the water is a very important part of pool maintenance. Accordingly, it is no wonder that pool owners want to have accurate results when checking the water.

For these accurate measurement results, it pays to use products from well-known brands and manufacturers that have proven themselves over the years. Among others, the following manufacturers are known for their pool measuring devices:

  • Hanna Instruments
  • Testo
  • Hach

Correctly adjust pool water pH

Regular testing of the pool water pH is a basic requirement for proper pool chemistry treatment. For this reason, you must test the pool water at least every week.

If the pH is too high or too low, you need to counteract it. This is where different pool chemicals come in handy. Below, we explain how you need to proceed step-by-step in doing so.

Lowering the pH value

A too high pH level in the pool promotes algae growth, causes skin and eye irritation, inhibits chlorine effectiveness and accelerates limescale formation. You can lower the pH with classic pool chemicals or household remedies.

The best way to lower the pool pH is to use pH Minus granules.

Note: The chemical pH Minus consists mainly of sulfuric acid. Most pool owners rely on pH Minus to lower the pH level in the pool. The reasons are the ease of use and the fact that the desired results occur without side effects.

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Spa Essentials 32519000 pH
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Step-by-step instructions:

  1. Measure the pH value of the pool water. This can be done with test strips, for example.
  2. Calculate the capacity of your pool.
  3. From this, determine the required amount of pH Minus Granules.
  4. Add the granules to the pool water.

Some forums also recommend vinegar as a home remedy for lowering pH. However, we do not recommend it. Using vinegar in pool maintenance comes with some disadvantages.

Vinegar is an organic acid that is a food source for bacteria and algae. Therefore, following the use of vinegar, it must be expected that the consumption of chlorine will increase and the filter will be more loaded.

Increase pH value

A too low pH value in the pool can cause damage to the pool materials (such as tile joints and metal parts), irritate the mucous membranes, worsen the effect of the flocculant and cause an unpleasant odor in the water.

If the pH value is too low over a long period of time, the pool can suffer severe damage. If you always measure the pH and readjust it, you can avoid the damage and avoid the high cost of repair.

The best way to raise the pH is to use pH Plus granules.

Note: pH Plus is sodium carbonate or soda ash. Even small amounts of pH Plus are enough to raise the pH level in the pool.

Many pool owners rely on the chemical to raise the pH level. This is because pH Plus is not only inexpensive, but also extremely efficient.

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Spa Essentials 32518000 pH
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Step-by-step instructions:

  1. Measure the pH value of the pool water. This can be done with test strips, for example.
  2. Calculate the capacity of your pool.
  3. Now determine the required amount of pH Plus granules.
  4. Add the granules to the pool water.

Some people on blogs and forums will also recommend that you prefer to use home remedies here. One popular option is to use washing soda. The procedure with washing soda is similar to the procedure with pH Plus granules. Only the quantity is adjusted. Thus approx. 5g soda per 10m³ water is needed, in order to raise the pH value around 0,2.

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Arm & Hammer Super Washing Soda
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Bonus: Automatically regulate pH value

If you’re a fan of home automation, you should look at dosing systems. Once these are properly configured, they measure the important values in the pool water (such as pool pH and chlorine levels). If the concentration of a chemical is too low, the dosing systems will independently release the correct amount of that chemical to bring the pool chemistry back into balance.

FAQ: Frequently asked questions about pool pH

Why does the pool pH change?

The change in pH can be attributed to natural circumstances, but it can also have other causes.
After the winter break: When you refill the pool after the winter break, there is a lot of carbonic acid in the water. The carbonic acid is bound to calcium carbonate. However, the turbulence of the water causes outgassing. Since the carbonic acid is acidic, the pH increases as a result.
Foreign particles: Most foreign particles are carried into the water by the bathers themselves. Hair, skin flakes, sunscreen and other skin care products get into the water directly through the pool goers. Likewise, leaves, pollen, foliage and small twigs also get into the pool.
Rainwater: acid rain is one of the biggest culprits of low pH. This is because rain washes carbon dioxide out of the air, which significantly lowers the pH. The higher the carbon dioxide concentration in the air before, the lower the pH of the rain, or the more acidic the rainwater. 

What is the right pH level in a hot tub?

The ideal pH level in a hot tub is between 7.0 and 7.4, so there is no difference between a hot tub and a normal swimming pool. In the range of 7.0 and 7.4, which is close to the neutral pH of 7.0, the materials are not affected, nor is there irritation of the eyes or mucous membranes of the bathers.

Is it still allowed to bathe if the pH is too high or too low?

Whether you are allowed to bathe with a pH value that is too high or too low depends on how far the value is from the optimal value. We recommend bathing only in the range of 7.0 to 7.4. Outside this range, undesirable side effects may occur.
The higher the pH of the water rises, the more dangerous the water is for humans. The optimal pH value is 7.2. From a pH value of 8.0, bathing is not allowed. Values from 9.0 and higher can already cause more severe damage to the mucous membranes and retina. It becomes life-threatening from the range of over 10.0.

How often should you measure the pH value?

The general answer is that you should measure the pH at least weekly. After a partial or complete water exchange, as well as in midsummer, it is recommended to measure the pH two days a week.
The reason for this is that directly after a fresh filling, the pH value initially changes strongly due to outgassing carbonic acid. In the summer season, the pool is used most intensively and the risk of algae formation is highest. Here it is necessary to be on the alert and observe the pool water even more closely.

Conclusion

At first glance, pool pH seems like an abstract concept. However, the topic is very important for pool owners. Only with a pH value in the ideal range (between 7.0 and 7.4) the pool water stays clear, the bathers don’t get problems with eye or mucous membrane irritations and the pool equipment as well as the filter system doesn’t get damaged.

We hope that you have realized the importance of regular pool water testing. In this article, we have presented various methods on how to record the pH level in the pool and what steps to take, if the pH level is too high or too low.

Whether you rely on analog or digital measurement methods does not matter much. The main thing is to check the pool water (and especially the pH) at least weekly and act if something is wrong with pH or the concentration of another pool chemical.

Larry has been a true water rat since childhood. Pure pleasure turned into a passion. That's why he is the first point of contact for friends and acquaintances when it comes to pool-related problems. He is an integral part of the PoolHandbook editorial team.