Caring for Pools During Excessive Heat and Wildfires

Q: How can a heat wave affect residential pools? 

A: Excessive heat impacts pools in many ways. First, warmer temperatures can increase the rate of evaporation, which removes both water and chemicals from the pool and alters water chemistry when new water is added. Second, warmer temperatures accelerate chemical reactions in the pool water, and algae activity increases. This combination of conditions causes sanitizers to be used up faster than normal, which can lead to bigger problems with algae and unsanitary water conditions. Finally, the likelihood of scaling issues increases, which can have serious implications for pool surfaces and equipment. 

Q: How can regional wildfires and this type of air pollution cause pool issues? 

A: Wildfires introduce a lot of soot and ash into the air, which can enter pools and impact water chemistry. Even pools far away from the actual fire can run into the same issues with pH changes and diminished sanitizer levels, as well as excess phosphates, nitrates and ammonia. 

The first step is to manually clean as much visible soot and ash from the pool as possible and keep the pump running 24/7 to circulate and filter water. Installing a skimmer sock or shield can help remove ash that has broken apart. Test the pool water, paying particular attention to pH, total alkalinity and phosphate levels, and treat the water as necessary. 

Once the water is balanced, shock the pool to oxidize any organic contaminants. This will also raise the free available chlorine level, which tends to drop quickly under smoky skies. Using enzymes can remove oils and nonliving organics, and adding an algaecide will help prevent an algae bloom. Ensure the free available chlorine levels are below 5 ppm before adding enzymes to the pool, or the chlorine will attack the enzymes. If the water is cloudy, use a chitosan clarifier to help quickly clear the water.

Q: What conditions cause algae growth? 

A: It’s hard for algae to grow in a well-maintained pool. If the pool isn’t cleaned with routine skimming and surface brushing, the pump isn’t run for enough hours each day, it lacks poor filtration or isn’t maintained with adequate sanitizer levels, it’s almost guaranteed to have frequent algae troubles. Pools high in phosphates and warm temperatures also accelerate algae activity and growth, so it’s especially important to test the water more often and run the pump longer during hot weather.

Q: How can pool owners and servicers combat algae or other unhealthy pool water conditions?

A: Maintain a clean, well-balanced pool, and always keep chlorine levels within the ideal range of 1–4 ppm. Sanitizer is the primary defense against algae, and maintaining a consistent free available chlorine level within the recommended range helps the water stay algae-free. For problem pools with lots of users, swimming animals or significant debris, the weekly use of enzymes and an algaecide can supplement chlorine. 

Algae grows more easily in stagnant water, so circulating water is also a deterrent for algae growth. Remind pool owners to run the pump for at least 8–12 hours per day or longer in hot or inclement weather. 

Excess organic debris in the water can use up chlorine quickly and provide a hiding place for algae. Daily skimming, weekly brushing and vacuuming as needed will help keep debris to a minimum. 

Other preventative measures include keeping phosphate levels low to eliminate algae’s main food source and using an algaecide weekly.

Q: What are the best tips to keep water safe to swim in? 

A: Remember the 3 Cs of pool care: chemistry, circulation and cleaning. These crucial tasks will help maintain a healthy swimming pool. It’s also important to remember that if there’s not enough chlorine in the water, it’s not safe for swimming. Maintain chlorine levels with a daily sanitizer, such as 3” chlorine tablets, and shock weekly to break down contaminants and chloramines. 

Even with proper sanitizer levels and regular shocking, improper water balance can have a negative impact on the way the chlorine works in the pool. Pool owners should keep up with weekly water tests and test more often in hot weather or after a storm or pool party. 

Q: How should pool owners and servicers combat evaporation? 

A: The average pool loses about one-quarter inch of water per day, but pools in hot, dry climates can lose as much as one-half inch daily, especially during a major heat wave. The most effective way to reduce evaporative water loss is to use a solar pool cover, which can reduce evaporation by 95%.  

It’s worth noting that solar covers will also add heat to the pool, so most pool owners don’t use them in the summer unless local laws require them for water conservation. 

An easier alternative is to add a liquid solar cover to the water during weekly maintenance. Liquid solar covers aren’t quite as efficient at reducing evaporation but still make a noticeable difference. For windy conditions or pools with a negative edge, most liquid solar cover brands will require a double dose. The heating effects are significantly less than a standard solar cover, so it’s a popular option during peak summer months. 

Q: Are there preventative steps servicers can take before the hottest parts of the summer? 

A: Test and balance the water more often and ensure sanitizer levels stay in the proper range. Also, increase the pool pump’s run time schedule by an hour or two (or more) to ensure adequate circulation. Using a robotic pool cleaner will not only help keep the pool clean, but it can also supplement water circulation during the hottest parts of the day, which helps prevent algae growth.

Q: Under what conditions should pool owners avoid swimming in their pools?

A: If water tests show chlorine levels that are out of range, stay out of the pool. Low chlorine levels allow microorganisms to take over and may make the water unhealthy for swimming. High chlorine levels, such as what you’d find immediately after shocking the pool, can be harmful to swimmers. Only get in the pool if the free available chlorine levels are between 1–4 ppm. An imbalanced pH may provide an uncomfortable swimming experience and impact the efficacy of chlorine for sanitizing the water.

Don’t get in the pool if the water is cloudy or full of algae. Both conditions indicate a water balance problem or lack of sanitizer, and algae can harbor germs. Water that’s not crystal clear can hide the floor of the pool, which increases the chances of drownings or other pool-related accidents. If there’s a fecal incident or other major water contamination event, follow the protocols recommended by the CDC to ensure proper sanitization of the pool.

Q: What should servicers be communicating to their clients/pool owners during a heat wave? 

A: Make sure customers are aware of any changes to their pool care routine — such as an increase in pool pump run time or the addition of extra chlorine tablets — and let them know to be on high alert for changes in water quality or scale forming at the waterline. At the first sign of an issue, the customer should contact you to address any water chemistry problems.