Swimming insects like water boatmen and backswimmers are often attracted to pools that provide a food source or a hospitable environment. The presence of these bugs, particularly the predatory backswimmers, often indicates that your water chemistry is not properly maintained. Eliminating these pests requires a multi-step approach involving immediate physical removal, targeted chemical treatment, and long-term preventative measures.
Immediate Physical Removal Techniques
A deep leaf net or skimmer is the most effective instrument for removing visible insects. Use a slow, sweeping motion across the water to capture insects floating on the surface or just beneath it. This technique avoids creating turbulence that might cause the insects to dive deeper or fly away, as both water boatmen and backswimmers have wings.
After skimming, manually vacuuming the pool is necessary to collect debris, sediment, or insect eggs that have settled on the floor. Water boatmen feed on algae, and backswimmers prey on them; both often lay their eggs in the pool’s lining or in organic matter. Thoroughly vacuuming the entire floor removes this material, disrupting the insect breeding cycle and preventing future generations from hatching.
Chemical Treatments for Insect Eradication
Eliminating the food source is the most direct method for eradicating swimming insects, as high chlorine levels alone are not always effective against adult bugs. Water boatmen are drawn to the pool specifically because they feed on algae and microscopic organic matter. Removing the algae, even if the water appears clear, eliminates the primary food source for the boatmen and, subsequently, the predatory backswimmers.
The primary chemical treatment involves shocking the pool to destroy algae spores and residual organic contaminants. A high concentration of sanitizer, often a double or triple dose of shock, must be introduced to elevate the chlorine level significantly above its normal range. For the treatment to be most effective, brush the pool walls and floor first to loosen attached algae, allowing the shock to penetrate.
Shock the pool in the evening because the sun’s ultraviolet rays rapidly break down chlorine, reducing its effectiveness. Running the filtration system for at least eight hours after shocking ensures the chemical is fully circulated throughout the water volume. Once the chlorine level returns to a safe range, test the water chemistry to ensure the pH and alkalinity are properly balanced before swimming. Specialized algaecides can also be applied to prevent initial algae growth, making the environment inhospitable for water boatmen.
Preventing Future Insect Infestations
Long-term prevention focuses on maintaining conditions that are unappealing to aquatic insects. Since poor water quality and the presence of algae are major attractants, consistent chemical balance is paramount. Keeping the free chlorine level between 1.0 and 3.0 parts per million (ppm) and the pH between 7.2 and 7.8 will inhibit algae growth.
Managing external lighting around the pool area is another highly effective deterrent. Many flying insects are drawn to light sources for navigation, a phenomenon known as phototaxis. Lights that emit high amounts of ultraviolet (UV) or blue light are particularly attractive to insects.
Switching to warmer-toned lighting, such as yellow, amber, or red LED bulbs, can significantly reduce the number of insects drawn to the pool at night. These colors are less visible to many common flying insects, making your pool a less desirable destination. Finally, using a pool cover when the pool is not in use provides a physical barrier, blocking access for both flying and crawling insects and preventing them from laying eggs in the water.