Summer is in full swing. The sun is beating down, temperatures are soaring, and your pool is the perfect refuge from the heat. But this pleasure comes at a price: during heatwaves, your pool water is put to the test. Accelerated evaporation, algae growth, pH instability... without careful attention, your water can quickly turn into a nightmare.
So, How to care for the water in your pool efficiently when the mercury rises above 35°C? What measures should be taken on a daily basis? Which products are best to use? And how can our ICO Pool AnalyserICO Pool connected analyser
Here you will find a comprehensive guide to preserve clear and healthy water even during a heatwave

Heatwave: How does it affect the balance of your swimming pool?
At temperatures above 28–30 °C, the heat affects the water in your pool. It becomes less stable and can change very quickly.
When your pool water is less stable, it deteriorates very quickly. This manifests itself in an imbalance in the water linked to:
- The proliferation of algae, bacteria and micro-organisms. Without treatment and appropriate measures, the water becomes cloudy and green.
- The very rapid evaporation of water: this has an effect on the speed of changes in the water balance.
- The development of limescale and tartar formation due to water evaporation. The water hardness (TH) of the water increases and must therefore be monitored very closely. This can also damage your equipment. Your pump may become unprimed and damaged in the long term.
- Treatment products become less effective over time, particularly chlorine, which is less effective at disinfecting water.
- The perspiration of bathers.
- When the outside temperature rises, it is important to monitor changes in the water so that you can act quickly and take the right maintenance measures.

Understanding the impact of heat waves on your pool water
Before taking action, it is important to understand the mechanisms that come into play when it is very hot. Heat waves alter several balances in your pool:
- Ein schneller Temperaturanstieg:
- More intense evaporation
- A constant chemical imbalance
- An increase in swimming
The right steps to take to keep water safe in hot weather
- Test your water daily or follow the treatment recommendations provided by your ICO Pool analyser.
- Turn on the water filter continuously
- Brush the walls and clean the bottom regularly, empty the skimmer baskets.
- Fight algae with preventive or curative anti-algae treatment
- Monitor the water level and top up if necessary.
- Protect the water from the sun by creating shade: parasol, shade sail, etc.
- Do not cover your pool at night

ICO Pool: a smart ally for monitoring water during heatwaves
- Automated analysis 24 hours a day
- Personalised alerts
- Tailored recommendations
- A history to anticipate
Find out more with the ICO app.
Mistakes to avoid when it's very hot
- Waiting for the water to turn before taking action
- Overdosing products
- Forget about filtration
- Close the pool completely
In summary: the special heatwave pool maintenance checklist
- Daily water analysis (pH, disinfection, temperature)
- Water level monitoring
- Extended filtration (at least 12 to 16 hours per day)
- Weekly cleaning of skimmers and brushes
- Preventive or curative algae control
- Personalised recommendations with ICO Pool
Enjoy your pool to the fullest, even at 40 °C
The heat should not deter you from swimming. On the contrary, a well-maintained pool is an indispensable oasis of refreshment during heat waves. By following these tips, you can ensure water quality, extend the life of your equipment and, above all, enjoy every dip in the water without worry.
And with ICO Pool, you no longer leave anything to chance. The app monitors, advises and alerts you. Summer can be hot, but your water will remain crystal clear.