How to Get Rid of Algae in a Swimming Pool

Swimming or even just soaking in a swimming pool is very fun not until you find algae and other elements swarming in the water. More than just the usual cleaning with a large net, owning a swimming pool comes with the responsibility to take care of them. Regardless if it is in a private home or a public swimming pool, a swimming pool needs to be properly maintained, or else, it could become unusable in no time. Prolonged neglect could also lead to more serious problems that could become bigger, harder, and costlier to fix. In this article, we will discuss one of the most common and natural problems that could occur in a swimming pool – algae – and how to fix them.


Algae is the informal term for a large group of aquatic plants that live and grow in water with their ability to conduct photosynthesis. There are over 800 species of its kind and they form colonies while floating in the water or being attached to surfaces. Algae are not harmful. We humans need them. Besides being an important part of the lower food chain, they also produce oxygen and capture carbon. They are hugely responsible for the decarbonizing process of our planet as over half of the earth’s oxygen come from the ocean. However, while algae do not harm humans, the bacteria that feed on it is the one we need to be worried about. Unlike lakes, sea, and natural waters that contain various aquatic life that cleans toxins and bacteria, swimming pools don’t have them. So swimming in a pool with algae means you are exposing yourself to bacteria which can lead to gastrointestinal issues and respiratory problems.

Common types of algae in swimming pools

Yellow algae – most of the time, yellow algae are mistaken as a patch of sand or stain and are mostly found in a shaded area of a swimming pool. Although less common than other types of algae, yellow algae are difficult to remove. Green algae – is one of the most common swimming pool algae and can be found in all areas of the pool. One of the obvious signs of green algae infestation is water turning green or cloudy. It grows so fast that it can fill an entire pool in just a few days. Black algae – these rough and slow-growing algae are mostly found at the bottom of the pool. It has either small or large rough caps and can embed on the concrete. Removal of these types of algae is complicated and would normally require the help of experts.

How to get rid of algae in your swimming pool


The best way to get rid of algae is to prevent them from existing in the first place. To do that, you have to always ensure the proper pH, calcium, alkalinity and cyanuric acid balance of the water. Chlorine levels should also be between 1.0-2.0 ppm and regularly shocked, and keep a regular and adequate dose of algaecide. Another prevention method is to ensure that the filter is enough for the pool’s size and is operating regularly. Make sure to filter the water once every 24 hours and keep it in check regularly. While chlorine can prevent and cure green algae, it is not the case for black algae. With black and yellow algae, you will need to have a stronger dose of chlorine or use a phosphate remover. Phosphates need to be prevented from entering the water as they promote and help the growth of bacteria and algae. Just make sure that you use an appropriate amount and keep the doses properly balanced.


The very first step to do after finding out that your swimming pool is swarmed over with green algae is to shock it until the water becomes blue or grey. Make sure to use an adequate amount of chlorine and pour it directly into affected areas. But before doing that, you need to clear your pool out of pool cleaners or solar blankets so they will not be affected by the high level of chlorine. Also, make sure to lower the pH between 7.2 and 7.4 for the chlorine to be as effective as possible. After shocking, brush the entire pool including the smallest nooks and crannies. After that, when your swimming pool water returns to its normal colour, it is a sign that it is ready and safe to use again. Make sure to check if you can see the bottom of the pool before deciding to jump in the water.


Regular cleaning and maintenance are necessary to prevent the regrowth of algae. Keep chlorine levels below 5ppm, ideally between 1-1.5ppm. Regularly check if the chloramine level is near zero. Keep the pH level and alkalinity balanced. Make sure that your filtration system is running the entire time you are clearing the algae. Backwash if the pressure gauge goes up to over 7lbs. Pour additional algaecides and purifiers a few days after shocking.

Ask professional help

Need help in clearing out the algae on your swimming pool? Contact Hot Tubs Staffordshire for a quick and reliable help. We are a team of swimming pool specialist that provides all types of related services from construction, refurbishment, cleaning, and more. Contact us for enquiries.

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