Pourquoi le pH de ma piscine continue d’augmenter ?

Why is My Pool pH Keeping on Climbing?

A persistently high pH in your swimming pool is more than just an annoyance; it can impact water clarity, sanitizer effectiveness, and even your swimmers’ comfort. Understanding the root causes is crucial for effective treatment. While a slightly elevated pH might seem minor, consistent increases require attention to avoid bigger problems down the line. Let’s dive into the common culprits behind a climbing pool pH.

The Usual Suspects:

• Alkali-based Chlorine Products: Many chlorine products, particularly granular forms and some liquid varieties, contain alkalizing agents. These agents raise the pH as they dissolve, a necessary trade-off for effective sanitization. However, overuse or improper application can significantly boost the pH beyond the ideal range of 7.2 to 7.8. Choosing a pH-neutral chlorine source, such as calcium hypochlorite, can help mitigate this issue, but careful monitoring remains essential.

• Water Temperature: Heat plays a crucial role. Warmer water simply holds less carbon dioxide (CO2), a naturally occurring weak acid in pool water that helps buffer pH. As the temperature rises, whether through a heater or solar cover, the CO2 level drops, pushing the pH upward. This means that maintaining a consistent pH during hotter months requires more frequent testing and adjustment.

• Calcium Hardness: High calcium hardness can contribute to pH elevation. As calcium carbonate precipitates, it consumes hydrogen ions (H+), thereby raising the pH. This is often a more gradual increase, but it’s important to consider if your calcium hardness levels are consistently high.

• Evaporation: While not a direct cause, evaporation concentrates the pool’s chemicals, including those that raise pH. As water evaporates, the remaining chemicals become more concentrated, leading to a potential pH increase. Regular topping off with fresh water helps to counteract this effect.

• Incorrect Chemical Addition: Adding the wrong chemicals or adding too much of the right ones is a common mistake. Always follow the manufacturer’s instructions carefully and use a reliable test kit to monitor levels before adding any chemicals. Improper addition of alkalinity increasers, for example, will directly raise the pH.

• Splash-in Contamination: While less common, contaminants brought in by swimmers, such as lotions, sunscreen, or sweat, can subtly influence pH levels over time. Regular maintenance, including proper filtration and regular backwashing, helps mitigate the effect of these external factors.

Taking Action:

Addressing a persistently high pH requires a multi-pronged approach. Regular testing with an accurate test kit is paramount. Once elevated pH is identified, gradually lower it using a pH decreaser, following the instructions precisely. Consider the underlying causes identified above to prevent future increases. Regular maintenance, balanced chemical levels, and appropriate water temperature management are key to keeping your pool’s pH within the ideal range. If you’re struggling to maintain your pH, consider consulting a pool professional for expert advice and guidance.