Six Ways to Safeguard Your Pool During High Temperatures and Heat Waves

When the temperature soars, your pool requires some additional care to remain sanitized. Excessive heat and extended sun exposure can lead to problems like algae growth, increased evaporation, and quick changes in water chemistry. Luckily, there are several measures you can take to maintain balance. Here are six effective methods for keeping your pool water in great condition during hot weather. Let’s dive right in.

1. Test Your Pool Water Frequently

Typically, testing your pool water once a week is sufficient. However, when it’s extremely hot, water chemistry can fluctuate rapidly. Aim to test your water two or even three times a week during heat waves. This will allow you to catch any imbalances before they become major problems.

Chlorine levels tend to be the most affected by heat and sunlight since UV rays cause it to degrade faster. Be extra mindful of chlorine drops. Also, keep in mind that if the pool is being used more frequently—due to the hot weather—this too can impact water chemistry.

2. Increase Your Chlorine Levels

With higher temperatures, algae tend to thrive, which causes chlorine to be used up faster. Additionally, sunlight causes chlorine to break down at a quicker rate, so you might notice a significant decrease in chlorine levels when the weather heats up.

To keep free chlorine levels between 1 and 3 PPM (with 3 PPM being ideal), maintain your routine chlorine dosing, and consider shocking your pool weekly to keep the chlorine active. If free chlorine drops too low, shock your pool using cal-hypo shock, dichlor shock, or liquid chlorine. This will boost chlorine levels and destroy any contaminants or algae. If free chlorine levels are within the ideal range, opt for a non-chlorine shock (oxidizer), which helps clear out used chlorine without adding more to the water.

If you start seeing algae growth, a double or triple dose of chlorine shock may be necessary to eliminate it. For more details on eliminating algae, refer to our guide.

3. Maintain Proper CYA Levels

Cyanuric Acid (CYA), often referred to as a chlorine stabilizer, protects chlorine from rapid breakdown caused by direct sunlight. In hot weather, ensuring your pool’s CYA levels are between 30 and 50 PPM will help preserve chlorine. Dichlor granules and chlorine tablets already contain CYA, but if you’re using chlorine products without stabilizer, you may need to add CYA separately.

For saltwater pools, maintaining CYA levels is particularly important since saltwater generators don't introduce CYA naturally. Many saltwater pool owners find that keeping CYA between 60 and 80 PPM reduces the workload on the generator, especially during periods of intense sun exposure.

4. Stay Ahead of Algae Growth

Algae thrive in warm water, so you’ll need to step up your cleaning routine during heat waves. Brush the pool walls and floor frequently, ideally more than once a week, and vacuum the pool regularly to remove any algae spores that may be present. A robotic pool cleaner can be especially helpful during this time, and it’s worth running it more often when temperatures are higher.

5. Extend Your Pump’s Run Time

Running the pool pump for longer periods helps prevent algae from taking hold. When water is constantly moving, algae have less chance to attach to surfaces and grow. In addition, the pump helps circulate chemicals throughout the pool and filters out debris and contaminants.

If you normally run the pump for about 8 hours a day, consider adding an extra hour or two during particularly hot weather. When temperatures exceed 100ºF (37ºC), it’s wise to run the pump for even longer. For those using a variable-speed pump, try running it at a low speed 24/7 during the hottest days.

6. Use a Solar Cover to Prevent Evaporation

Heat accelerates evaporation, which not only reduces water levels but also causes chemicals to evaporate. A solar pool cover is an effective tool to combat this, potentially reducing evaporation by up to 95%. Make it a habit to cover the pool when it’s not in use, especially at night, since cooler temperatures can exacerbate evaporation.

Be sure to complete all other maintenance steps before using a solar cover, as it can create an environment that encourages algae growth if the water isn’t properly balanced.