Pool Water Treatment: pH, Chlorine, Salt — A Comprehensive Guide for 2026
Proper pool water treatment is key to a healthy swimming experience and a long-lasting pool. If the chemicals aren’t properly balanced, they can irritate the eyes, corrode equipment, or allow bacteria and algae to thrive. At POOLRITUAL, a leading pool specialist in the Gulf of Saint-Tropez, we treat the water in hundreds of pools every year. Here is our comprehensive guide to understanding and mastering your pool’s chemistry.
1. Why is water treatment essential?
A swimming pool is not a closed system. Every swimmer, every leaf, and every ray of sunlight alters the water’s chemical balance. Without regular treatment, bacteria multiply, algae colonize the walls, and the water becomes cloudy or hazardous to health. In the Var region, the summer heat and intense sunshine of the Gulf of Saint-Tropez accelerate these processes: untreated water can become problematic in just a few days.
2. pH: the most important parameter
pH measures the acidity or alkalinity of water on a scale from 0 to 14. For a swimming pool, the ideal range is between 7.2 and 7.4. Outside this range, all other treatments become less effective.
pH too low (acidic water): eye and skin irritation, corrosion of metal equipment, discoloration of the liner.
pH too high (alkaline water): chlorine ineffectiveness, scale buildup, cloudy water, skin irritation.
To adjust the pH, use a pH-lowering agent (acid) or a pH-raising agent (base), adding it gradually according to the manufacturer’s instructions. In the Var region, tap water is often hard, which tends to naturally raise the pH: weekly monitoring is recommended.
3. TAC and TH: the stabilizers
The TAC (total alkalinity) measures the water's buffering capacity, that is, its resistance to pH fluctuations. Ideally between 80 and 120 mg/L, it prevents sudden pH spikes.
The TH (total hardness) measures water hardness. At levels between 10 and 25°f, it helps prevent limescale buildup on walls and equipment. In the Gulf of Saint-Tropez, the water is often hard, so a water softener may be necessary.
4. Chlorine: the go-to disinfectant
Chlorine remains the most commonly used disinfectant for swimming pools. It kills bacteria, viruses, and algae. The ideal level for a private pool is between 1 and 1.5 mg/L (ppm).
Slow-release chlorine (tablets): for routine maintenance, with gradual release.
Shock chlorine (granules): for emergency situations (green water, high usage, after a storm).
Stabilized chlorine: contains cyanuric acid, which protects the chlorine from UV rays. Note: If the cyanuric acid level is too high (>75 mg/L), it reduces the effectiveness of the chlorine.
Note: Chlorine works properly only if the pH is within the correct range. That is why you should always adjust the pH before correcting the chlorine level.
5. Salt electrolysis: a gentle alternative
Growing in popularity on the French Riviera, salt water chlorinators naturally produce chlorine from salt dissolved in water. The result: softer water that doesn’t smell like chlorine and is gentler on the skin and eyes.
Benefits: more comfortable water, fewer chemicals to handle, lower long-term maintenance costs.
Disadvantages: higher initial investment, maintenance of the electrolysis cell, monitoring of the salt level (3 to 5 g/L).
POOLRITUAL installs and maintains salt water chlorinators throughout the Gulf of Saint-Tropez. We can advise you on the model best suited to the size and intended use of your pool.
6. Phosphates: The Silent Enemy
Phosphates occur naturally in rainwater, leaves, sweat, and sunscreen. They are the primary food source for algae. High phosphate levels (>0.1 mg/L) promote algal blooms even in the presence of chlorine. The use of a phosphate remover at the start and throughout the season is recommended, particularly in the Var region, where surrounding vegetation contributes to phosphate levels.
7. Should you hire a professional for water treatment?
For simple pools with low usage, a knowledgeable owner can manage water treatment on their own using a good test kit. However, for complex systems, hotel pools, or pools subject to heavy use, hiring a professional pool specialist like POOLRITUAL ensures impeccable water quality without the risk of overdosing or misreading test results.
Our team conducts comprehensive analyses and makes precise adjustments during each visit, providing a detailed report for professionals.
FAQ — Your Questions About Water Treatment
How many times a week should you test your pool water?
During the swimming season (May through September), a minimum of one test per week is recommended for private pools. For high-traffic pools (such as those in hotels and apartment complexes), daily or twice-daily testing is required and is often mandated by regulations.
Can you go swimming right after adding the products?
No. After adding shock chlorine or adjusting the pH, you must wait at least 4 hours for the filtration system to run before swimming, and check that the levels have returned to the normal range.
My pool water is green: what should I do?
Green water indicates an algal bloom. First, check and adjust the pH, then perform a chlorine shock treatment, let the filtration system run for 24 to 48 hours, brush the walls, and vacuum the bottom. If the problem persists, contact POOLRITUAL for an on-site assessment in the Gulf of Saint-Tropez.
Contact POOLRITUAL: www.poolritual.com/contact-devis-gratuit-pisciniste
Phone: 04 94 20 83 70 Address: 79 Place de la Gare, 83240 Cavalaire-sur-Mer
POOLRITUAL – Pool maintenance, care, and design in the Gulf of Saint-Tropez.
