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Although chlorine alone won't keep bugs out, it will help keep the pool clean and hinder the growth of any bug larvae. 1-4 ppm (parts per million) is a safe range for swimming, and a 3-4 ppm level in particular is best for keeping the pool clean and bug-free. You can choose from a variety of chlorine forms to use in your pool, such as tablets, granules, or liquid chlorine. Use a testing kit daily to check your pool's chlorine levels and decide how much you'll need to replenish them. To apply the chlorine, follow the instructions that come with your product. For example, you'll likely place chlorine tablets in a floating dispenser, skimmer, or automatic chlorinator, then wait 1-3 minutes for it to dissolve. A cover is a necessary addition to your pool, especially when it comes to sealing out any pesky bugs. Use the cover during swimming season by taking off the cover whenever you're ready to use the pool and replacing it whenever you're done swimming. In the cooler months, when the pool isn't being used, keep the cover on permanently. If you don't already have one, you can purchase a cover and manually place it over your pool's surface. You can also have one installed with an automatic or semi-automatic cranking system. Purchase a pool cover from a home improvement store or through a cover installation service. After placing the cover over your pool when the weather grows colder, make sure to monitor it closely. If any water collects from rain or nearby sprinklers, sweep it off onto the grass or dry it up with an old towel. Water turns stagnant after sitting for about 9 days, so check at least once a week. Checking once a day would be even better! Use a shop vac to remove large amounts of sitting water. If water seeps through a tear in the cover, repair the area as soon as possible. To protect your patio and pool area from unwanted pests, you can put up a steel structure covered with fine netting walls around your entire swimming pool or deck area. You can either hire someone to install it for you, or you can put it up yourself with screen poles, quick-setting concrete, and a sheet of wire mesh. Keep in mind that this is the most extreme and expensive way to keep mosquitos and other bugs out of your pool area. This structure typically costs between $3,600 to $12,000 to install, so only use this option if you can afford it and it's absolutely necessary. This method works especially well in areas like Florida and other Gulf Coast states, where mosquitos can run rampant and pose a real health problem.
Chlorinate your pool daily to keep it at 3-4 ppm. Place a cover over your pool when it's not in use. Drain any sitting water on your pool cover at least once a week. Build a screened enclosure if you live in a tropical environment.