Your pool water analysis to-do list

What parameters need to be analyzed regularly to maintain your pool? In this article, you'll find a practical guide to the tests you need to carry out regularly to analyze your pool water. We give precise answers on the thresholds to be respected for each parameter in order to maintain balanced water quality. You'll also discover the right way to perform your tests to obtain reliable results.

Parameters to measure for perfect pool water

Your pool water is constantly changing. Several factors influence water quality. Depending on the weather, water temperature, your pool's environment or even the number of bathers, the water alters. The key is to maintain a balance between three different parameters: acidity, alkalinity and hardness. To achieve this, it's essential to analyze your pool water regularly. Well-balanced water is healthy water, which is essential for the health of bathers and the durability of your equipment.

Water parameters to be measured at least once a week

In the high season, your pool water needs to be analyzed on a regular basis. This allows you to intervene quickly with the right treatment, so you can continue to enjoy your pool every day.

• The ideal pH of the water is different depending on your means of disinfection:
  • For chlorine disinfection, it is between 6.9 and 7.4
  • For bromine or salt disinfection, it is between 7.5 and 7.8
• The ORP / Redox determines the effectiveness of your disinfectant (bromine, chlorine).
  • For optimum disinfection of water at 25°C, ideal ORP measurements should be between 650 and 750mV. This is one of the parameters that varies most rapidly because it depends on pH and UV values.
• The water temperature must also be kept under control.
  • Pool water that's too warm reduces the effectiveness of chemicals, which can lead to algae growth.

Water parameters to be measured once a month

• TH measures water hardness. The TH is indicated in French degrees (°f). Ideally it should be between 10°f and 20°f. Below 10°f, the water is too soft, leading to corrosion. Above 20°f, water is too hard. The water then becomes cloudy and milky, limescale deposits appear.
• The TAC determines the alkalinity of water. It is an essential element in water balance, along with pH and TH (water hardness). TAC should be between 100 and 200 mg/litre or ppm. A well-balanced alkalinity determines the water's buffering capacity and has an impact on pH stability and water acidity.

Water parameters to be tested twice a year

Stabiliser levels is a parameter to be tested (chlorine or salt pools). The ideal level is 20 to 30 mg/L. Above this level, your water risks being over-stabilised. An overdose of chlorine makes it ineffective, leading to the proliferation of bacteria, algae and fungi.

How to carry out reliable analyses of your pool water?

Different pool water analysis tools

To test the various water parameters, you can choose between the manual method with test strips and electronic testers, or the automatic method with connected water analyzers.

To test pH, for example, you can opt for a chemical reaction strip, a ph-meter, which is a handheld probe, or a connected water analyzer. Please read our comparison of pH measurement tools.

Pool test strips

Test strips, which are the most affordable in terms of price (between 20 and 30 euros cents per test), give results that are more or less reliable and precise. In fact, reading the result is an interpretation of the color indicated. If your water needs chemical treatment, it will be difficult for you to know what dosage of product to add.

There are, however, test strip readers available. Once the test strip has been dipped in water, the required values are displayed digitally on the screen. This compensates for any misinterpretation of colors. It's an additional investment (approx. 100 euros) that can prevent many misinterpretations and, above all, over-consumption of chemical products.

Test strips are available for specific disinfection methods: chlorine, bromine, salt or active oxygen. Depending on brand and product, they can analyze from 4 to 7 parameters. For reliable results, store them at room temperature, close the cap tightly and do not exceed the expiration date.

Pool electronic testers

Electronic testers or probes are much more reliable, but it's best to avoid the low-priced gadgets. These devices allow you to read a very precise digital result. However, they need to be calibrated regularly (depending on the model). You can ask your specialist for advice, as he or she is familiar with specialist pool brands.

Finally, some testers analyze only one parameter (pH or ORP), while others allow you to test several water parameters, which is more economical and, above all, more practical!

Connected water analyzers

For the past five years, the market for connected sensors has been booming. The key benefit of these devices is their ease of use, since the main parameters of your pool water are measured automatically every day, several times a day. Some connected sensors like ICO Pool give you access to the results of your measurements on your smartphone, along with chemical treatment recommendations with the right dosage. Thanks to ICO, pool maintenance tips, such as filtration or winterization, save users a lot of chemicals and time! Read the comparative report on connected probes.

How to do a reliable water testing

Before comparing the various pool analysis tools, it's important to remember that whatever the method used, it's important to carry out the analyses under the right conditions to obtain reliable results.

Que vous utilisiez une bandelette colorimétrique, un testeur électronique, voici la méthode pour faire votre test :

• Where to test? Perform your test in the middle of your pool, and test the water as far away from the edge as possible. In fact, water on steps or a submerged beach is less representative than water in the middle of the pool.
• Taking a water sample: to use this system correctly, you first need to take a water sample 40 cm below the surface. This is because the water at the water line is warmer and has a different composition. Of course, your container must be very clean, with no trace of chemicals that could pollute the result. Immerse your test strip in the water for 5 to 10 seconds before reading the result.
• Immerse a test strip: immerse the test strip in water (always favouring an area in the middle of the pool) and read the result immediately. Depending on the brand used, the result should be read between 5 and 15 seconds after immersion. The color continues to vary for several minutes, so it's important to read at the right moment.
• Using an electronic tester: Place your tester under the surface of the water (3cm minimum) then wait 5 to 10 seconds before raising your tester to read the result.
• When to do a water test: it's best to do your test in the morning or evening, but always at the same time! This allows you to compare your results from one test to the next.

Water analysis and pool maintenance, the right combination for crystal-clear water

To keep your pool water balanced, good pool maintenance is just as essential as regular water analysis. Maintenance must be regular (at least weekly in high season) and thorough: from cleaning the walls and water line to cleaning or replacing filters and pre-filters. On average, 30 minutes of maintenance every week is enough to keep your water crystal-clear. All you have to do is enjoy your bathing!