In summer, the domestic swimming pool offers a real alternative to overcrowded outdoor pools. But that only applies if the water quality is right. These measures help to lower the pH value.

In a nutshell

  • Even small deviations in the pH value have serious effects on technology, bathers and chemical requirements
  • any acid is capable of lowering the value
  • an accurate calculation of the tank volume and acid requirement is essential to achieve the target value

Why is too high a pH dangerous?

Depending on the pH value, water is either acidic, neutral or basic. A value between 7.0 and 7.4 is usually ideal for the water in your pool, because then the water quality is neutral to minimally alkaline. If, on the other hand, the value rises above this limit, one speaks of a so-called alkalosis. Up to 7.5 it is still a slight alkalosis. All values above this, on the other hand, are a case of severe alkalosis, which must be assessed critically from various points of view:

  • Reduced effectiveness of the chlorine
  • As a result: rapid formation of algae and multiplication of microorganisms
  • Damage to human skin due to drying out and degreasing
  • In the long run, there are further health risks due to impairment of the oxygen uptake of the blood (blood pH value around 7.4), resulting in dizziness and nausea
  • Increase corrosion on metal components (rust)
  • Overall increased stress on all pool components

Notice: Depending on the pool size and structure, the ideal value for the water quality can vary slightly within the framework shown. Therefore, when purchasing the pool, let the manufacturer advise you on the individually optimal pH value.

pH test strips

How do you actually measure the value of water quality? There are various technical possibilities for this. So-called pH test strips are the most common in the private sector. Briefly hold the strips in the water of your pool and wait for the indicator paper to change color. You can then read the exact pH value using the enclosed color table.

Notice: The pH value must always be evaluated using the associated reference cards! If you use the color chart of other test strips, the colors may differ and falsify your result!

If you suspect your pH is too high, it is important to always take an accurate reading before proceeding. Various factors can cause the value to change within a few hours:

  • water temperature
  • sun exposure
  • Other substances in the pool water (pool chemicals, dirt, etc.)
  • Use by bathers

Then it can happen that you want to act, but your efforts are going in the wrong direction or are even no longer necessary.

How big is my swimming pool?

No matter how you want to rebalance your pool water, the most important parameter for all measures is the water volume. Because the total amount of water additives required always results from a specific requirement per cubic meter of pool content. This is how you can easily determine the amount of water in your pool:

Rectangular floor plans:

  • Length x width x water depth (in meters) = water volume in cubic meters
  • For example: 4 meters wide, 7 meters long, 1.20 meters deep
  • 4.00m x 6.00m x 1.20m = 28.80m3

Round floor plans:

  • Base area according to the circular formula Pi x radius squared x water depth (in meters) = water volume in cubic meters
  • For example: 4 meters in diameter, 1.20 meters deep
  • 3.14 x (2.00m)² x 1.20m = 15.07m3

Tip: You can also easily calculate a pool with a different layout. Simply subdivide the base area into roughly matching rectangles and circle sections. You can then calculate these as described and add them up.

Lower the pH

If the value of your pool water is too high, you ultimately have no choice but to use chemicals to get back into the acceptable, medium pH range. You have several options for doing this:

pH reducer

Many suppliers of pool accessories offer special pH reducers. These come either as granules or as an aqueous solution and are added to the water. These special agents usually contain various inorganic acids, such as:

  • phosphoric acid
  • hydrochloric acid
  • other acids

Depending on the product and manufacturer, the acidity and thus also the requirement can vary depending on the desired pH reduction per cubic meter of water. Be sure to observe the dosage instructions, as well as general hazard and usage instructions for handling the products.

vinegar

If you want to do without expensive pool chemicals from specialist retailers, you can also use other acids, which are usually much cheaper. Vinegar, for example, is a good choice. Vinegar is also an organic acid and is therefore safe to use. Make sure, however, that it is pure vinegar essence, as the following frequently encountered admixtures are culinary exciting, but only have disadvantages for your pool:

  • Sugar (e.g. in balsamic vinegar) - sugar promotes bacterial growth
  • Unfiltered natural vinegars - cloudy substances etc. as a breeding ground for bacteria
  • Other flavorings and additives

citric acid

Pure citric acid from household supplies is also ideal for reducing the water characteristics of your pool. The advantage of this substance, which is mostly used for containment, is its high purity and the absence of disadvantageous admixtures. Normally, citric acid comes as a crystalline powder that is easy to add to water.

hydrochloric acid

Theoretically, the use of low-dose hydrochloric acid would also be possible. However, you should only use hydrochloric acid if you have the necessary knowledge of handling the hazardous substance. If used improperly, there is a high risk of chemical burns and permanent damage to the lungs or eyes.

Notice: If you opt for home remedies that are not specifically offered for the pool, the dosage will usually be less precise than is the case with special pH reducers. Slowly feel your way forward and test the result you have achieved over and over again. Otherwise, you can easily overshoot your target and cause hyperacidity.

How do you proceed?

Used incorrectly, you can achieve completely different, often negative effects with pH-lowering agents in addition to “more acidic” water. So make sure you use it correctly.

the initial situation

Since changes in the temperature, the amount of water, the pool chemicals used, but also possible cleaning processes can have a strong influence on the characteristics of the water, you should adjust the value under conditions that correspond as closely as possible to later bathing operations. For example, the afternoon on the day before the pool is open is a good time. The late evening or early morning hours are rather unsuitable, since the water temperature and sunshine then deviate significantly from the times of use.

The sequence

If the value is too high, you can lower it step by step with these measures:

  • Operate pump system for sufficient water movement
  • Put the pH reducer freely into the pool water
  • Keep the circulation running for about 10 minutes to ensure the water balance throughout the pool
  • Measure pH using test strips
  • add more pH reducers if necessary

Attention: Never put the acids directly into the skimmer, the filter system or other technical components. Otherwise there will be an extreme drop in pH, which can damage sensitive components in a short time.

frequently asked Questions

The pH keeps rising - what to do?

The search for the cause here is highly dependent on your individual circumstances. A probable cause is regular post-chlorination. Due to its chemical properties, chlorine is able to increase the pH value.

How concentrated do acids have to be to reduce pH?

Ultimately, you can use any acid regardless of the concentration. However, weaker acids must be added in larger amounts than stronger acids.

My pH value deviates little from the target range of 7.0 - 7.4. Do I have to act?

Technical components may still be able to cope with small deviations quite well. Above all, the human organism reacts very sensitively even to small deviations. The effectiveness of the chlorine also decreases sharply with small deviations. The result would be reduced water purity or a significantly higher chlorine content.

Category:

Garden design