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Why is My Pool Green? How to Keep Your Water Crystal Clear

My above ground pool is green

One of the best ways to beat the heat on a hot summer day is to go for a swim. If you have your own pool, you know that maintenance is no small task. The last thing you want as a pool owner is to discover that your pool water is green and cloudy instead of crystal clear.

Why is My Pool Green?

Keeping a pool looking clean and clear requires paying special attention to the water chemistry. Let’s discuss the three basic factors in pool operation—physical, chemical and biological—how they impact the color of your water and what to do if your pool water becomes cloudy and green.

Pool Filtration & Circulation

The most basic part of your pool’s operation is your filtration system, which is responsible for keeping your water clean. The filters in your pool should remove dirt and debris which make their way into your pool from the air or from your bathers and can contribute to cloudy water. The three most common types of filters are cartridge filters, sand filters and diatomaceous earth (DE) filters. Each type requires slightly different maintenance, although all benefit from frequent rinsing to remove accumulated debris.

In addition to making sure your filters are working properly, pool owners need to make sure that water is circulating through the pump and filter system. There are a few ways to keep water moving in your pool. First, check to see if the drain at the bottom of your pool is open so that at least one-third of the pool’s water flows through it. Second, direct your pool’s water flow in a circular pattern by changing the return line fittings. Finally, point these toward the bottom of the pool to help circulate water from the bottom of the pool to the top.

Sometimes, tiny particles in your pool make it past the filter, and a buildup of these materials can make your water more cloudy. Adding a water clarifier will force the microparticles to bond together and be more easily captured by your filters. If your pool is extremely cloudy, such as when you open it for spring, you may want to add a liquid flocculant (sometimes referred to as “floc”), which causes buildup to settle on your pool’s floor, where it can be easily vacuumed.

Over time, accumulation of makeup products and body oils can compromise the performance of your pool sanitizer and lead to unattractive scum lines. When that happens, homeowners can apply enzyme digestive products specially formulated for pools to help break down materials so that they can be handled by the pool’s filtration system.

Swimming Pool Water Balance

Your pool contains a number of chemicals to keep the water clean, clear and safe for swimming. The most common pool chemicals are water balancers, sanitizers, algaecides, oxidizers (more commonly known as “shocks”) and supportive pool chemicals. Part of the process of maintaining a pool is to ensure that the levels of these additives stay within a defined set of parameters.

An imbalance of the chemicals in your pool can promote the growth of algae that will turn the pool green, but the pool water can also turn green because of a buildup of minerals. Discoloration that is a result of mineral buildup tends to occur after chemicals are added to the pool. Algae growth is often the result of a lack of chemicals needed to keep the pool clean.

Biological Factors in Maintaining Clean Pool Water

Once you have taken steps to ensure that your water is filtered and circulating properly and that the pool chemicals are in balance, you’ll want to make sure your water stays clean. The primary ways to make this happen is to practice proper sanitation, to perform shock oxidation treatments, when necessary, and through algae control.

The most common pool sanitizers are chlorine and bromine. Both control the level of bacteria in your pool water. Shock oxidation helps prevent the buildup of bather waste, such as perspiration, which can combine with chlorine to irritate bathers’ eyes and mucous membranes, compromise chlorine’s ability to disinfect your pool water and which can lead to a strong odor.

After a storm or heavy rainfall, your pool may experience an influx of debris or organic material which may lead to algae growth or combined chlorine. Administering a shock oxidation treatment after these major weather events can help avoid these problems.

The easiest way to control algae is to prevent it in the first place. The most common types of algae found in pools are green algae, yellow (or mustard) algae and black algae. Use an algaecide as part of your routine pool maintenance which treats existing growth and discourages new growth.

Let ABC Be Your Expert on Pools

Still having trouble keeping your pool water looking clean and clear? Contact ABC Home & Commercial Services to handle your pool cleaning, repairs and routine maintenance. For decades, ABC has been making life easier on homeowners, whether it’s by handling pool maintenance to avoid costly repairs, handling landscaping and lawn care needs or even keeping your yard mosquito-free. Rely on the experts at ABC so you can spend your time enjoying your outdoor spaces.

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