pH level in water: a crucial pool maintenance aspect

pH is a measure of the concentration of hydrogen ions in water. It is expressed on a scale of 0 to 14, in which:

• pH levels around 7 are considered neutral
• Anything below 7 is considered acidic
• Anything above 7 is alkaline or basic

Regarding pH level in a swimming pool, the recommended range is between 7.2 and 7.8, with 7.4 being the ideal value. This is an essential measure, as water that’s too acidic or too alkaline can cause a myriad of problems, from skin irritation to damage in pool equipment, green water and cloudy water.

Regular testing of pool water is vital to ensure the pH level is within the recommended range. A solution is to perform manual water pH tests.

The water pH test must be undertaken periodically and with no exceptions, since pH levels fluctuate due to factors that are all part of the everyday use of a swimming pool: from rainfall to temperature changes, external debris, sunscreen lotions and swimmers themselves, all play a part in dysregulating pH.

While a weekly test is usually sufficient, more frequent water pH tests might be needed during the warm months or if the pool is being used more intensively.

Performing a pool water pH test is a simple operation: pool operators must use a pH testing kit, which can be purchased from pool supply stores, and which typically includes testing strips or a liquid reagent, a color chart, and instructions on how to perform the test.

Then, the following steps need to take place:

1. Collect a sample of pool water by dipping a clean container into pool water.
2. Follow the instructions on the pH testing kit. Usually, they guide users to add the test strip or liquid reagent to the water sample and then compare the resulting color to the colors that appear on the provided chart. The color of the water will correspond to a particular pH value, indicating whether it falls within the recommended range.
3. Adjust the pH level in water. If the pH level is outside the recommended range, you will need to adjust it. This must be done by either adding a pH increaser (soda ash) that raises pH levels or adding pH decreaser (muriatic acid) to lower it.

Achieving pool water quality involves a combination of different elements, all at optimal parameters. In fact, flawless pool water must be understood as an ecosystem in which all elements and systems are connected and need to work side by side.

Alkaline salts are calcium and magnesium. Controlling their levels (which are expressed in ppm or mg/l) means alkalinity is managed, so that sudden pH changes are prevented.

This is not only crucial for avoiding the issues we’ve mentioned above in terms of bathers’ health: correct alkalinity levels are also key to ensuring chlorine treatments, which can disinfect water effectively. In such a context, the recommended range for a swimming pool’s total alkalinity is between 100 and 150 ppm. 

This level refers to total alkalinity . And that is the ability of pool water to resist pH changes so that, when a substance and other pool chemicals are added to pool water, total alkalinity will react to maintain the pH level in water in the desired range (7.2 – 7.8).

On the contrary, high alkalinity can translate into an uncontrolled increase in pH, cloudy water, irritation in the eyes, throat and ears, and scaling on the walls and pool accessories. In turn, as we’ve mentioned above, high pH decreases the effectiveness of chlorine and other disinfectant treatments.

In scenarios where high alkalinity is detected, it’s possible to reduce it by adding acidic compounds and pH reducers, which come in liquid, powder or tablet formats. Once the alkalinity level begins to stabilize, it will take 48 hours to rebalance the pool’s pH levels.

Correcting low alkalinity is more complicated and requires greater precision, as it may cause pool pH levels to fluctuate. This scenario is usually caused by malfunctioning pool filtration systems or lack of adequate maintenance.

In such case, the most advisable thing to do is to calculate the volume of pool water and its pH at the time of maintenance. Then, an alkalinity increaser (usually sodium bicarbonate) is applied following dosage indications, essential to achieving the desired results.

Technological advancements have made it easier for pool operators to activate more precise and convenient maintenance. When it comes to guaranteeing the most suitable pH level in water, the automatic control systems offered by Fluidra are ideal to control large commercial or public pool facilities.

These technologies help operators maintain optimal water pH parameters at all times and automatically, making maintenance more efficient and sustainable while also providing a much sought-after peace of mind for operators. Among them, you may find:

• AP PR Series is the professional choice for control and dosing. Its integrated panels, which are based on controllers, make it a real ‘Plug & Play’ solution, as the system comes as pre-assembled equipment on a panel to control pH, ORP and free chlorine in the water. This system is compatible with electrolysis processes for maintaining water quality, adding to the pool’s hygiene and sustainability.
• Guardian Pool combines traditional control and dosing elements with total control of values through a digital platform. This technology facilitates pool parameter management, and allows operators to analyze and detect potential mistakes by using historical data.
• Acqua Dos pH/ORP dosing pumps work by dispensing pH correctors automatically according to the pH or ORP value reading.

All in all, automation solutions enable operators to ensure a correct pH level in water at all times while also freeing up their time. It’s a crucial step for achieving superb water quality, which in turn translates into a safe swimming pool for bathers and therefore a great swimming experience and a profitable pool facility.