How to get rid of algae from your swimming pool?

In this blog, we will learn the science to kill algae and how the growth of algae affects the functioning of your pool.

What are algae?

Algae is a non-flowering plant that typically includes seaweeds and many single-celled forms organisms. Algae is not your traditional plant and therefore lacks true stems and roots, leaves, and vascular tissues. However, like traditional plant algae does contain chlorophyll.

How do algae affect your pool?

Algae, over a period, can make your water smelly, and hamper the chemical balance of your pool. Overgrown algae can clog water filters and affect the water circulation in your pool. 

How algae enter your pool?

Algae enter your pool through the wind, rain, and other environmental factors.

How do you determine that your pool has algae?

It is not easy for a naked eye to determine the presence of algae in a pool just by looking at the water

colour. To be sure about the presence of algae and the type of algae in your pool you will have to closely observe the pools. Especially, at the corner, edges, and the parts of your pool that are mostly covered in shade.

Types of algae

Knowing the type of algae will allow you to identify the best method to treat your pool and minimize the growth of algae. So, let us learn the common types of algae found in your pool. 

Green Algae

Green Algae is the most found algae. It is called Chlorophyta and it gets its name due to the presence of chlorophyll. It is one of the easiest algae to remove or kill. Green algae float in the water thereby giving your pool water a cloudy appearance with a green tinge. This alga is slimy green in nature and attaches itself to the pool walls and floor. It can be introduced in your pool by water or swimwear that may have encounter natural water bodies. 

Yellow Algae

Yellow Algae usually grows in the shady corners of the pool. It appears brownish like sand or pollen. That is the reason why it is sometimes also referred to as Mustard Algae. It is a relatively rare form of algae and unlike the green algae, it is not slimy. However, this alga is chlorine resistant therefore difficult to treat.


Black Algae 

Black algae are cyanobacteria and therefore technically speaking it is no algae. Since it can make its own food it grows quickly thus making it very difficult to remove. Once black algae set its roots deep into concrete it is quite a task to remove it from your pool. Failing to remove the roots from your pool or treating your pool aggressively enough will give a back-door entry for black algae to grow again in your pool.

Methods to remove algae from your pool 

Clean the filter

Cleaning or replacing the filter is one of the easiest and effective solutions to tackle the problem of algae in your pool. How? It is quite simple, if you have a D.E. filter, set it to backwash. And, if you have a cartridge filter remove, and clean the cartridge with a hose at high pressure, followed by dilute muriatic acid or liquid chlorine treatment if necessary. Thorough cleaning of the filter is necessary as dead algae may block the filter.

Test and balance your pool water

Regular examination of the pool is necessary to kill algae in your pool. Test the pool again for the new chlorine and pH levels and the presence of algae.

⦿ If your chlorine levels are higher (2–5 ppm) but the algae are still there, keep maintaining these levels as usual for the next couple days.

⦿ If chlorine levels have risen but are still below 2ppm, shock a second time the next evening.

⦿ If there was no significant change in your chlorine levels, your pool likely has too much cyanuric acid (more than 50 ppm). This comes from using granulated or tablet chlorine and can “lock” your chlorine into unusable forms. The only way to fight this is to shock repeatedly (sometimes many times) or to partially drain your pool.

⦿ Large amounts of leaf litter or other objects in the pool can also eat up your chlorine. If the pool has been unused for a long time, this could take a full week and several shock treatments.

Brush the walls and floor of the swimming pool.

Brushing helps physically remove the algae off your pool. So, use your brush vigorously to remove as much of the algae as possible. Brushing will significantly reduce the amount of time it takes to kill and stop algae from growing. Take extra care while cleaning the steps ladders, and other nooks and crannies where algae tend to gather. Use brushes that are compatible with your pool like, steel brushes work well on concrete, and nylon brushes are preferable for vinyl pools

Review pool chemical safety

Cleaning and treating chemicals require handling dangerous chemicals. Therefore, before starting always read the safety information on the labels first. Adhere to all the safety standards for all pool chemicals:

⦿ Always cover your skin , wear gloves, eye protection. After use, wash hands and inspect clothes for chemicals.

⦿ Cover your face (mouth and nose) and avoid inhaling the chemicals, try to avoid handling in windy weather.

⦿ Always add chemicals to water, never water to chemicals. Do not place wet scoops back in the container.

⦿ Store chemicals properly in sealed, fireproof containers. These chemicals must be stored in a place where children cannot access the. Store every chemical on a separate shelf as many pool chemicals explode when they touch another pool chemical.

Use a chlorine shock product

Shocking is the process of treating your pool water with a large dose of chlorine, it is the most effective way to kill algae in your pool. Doing this will bring the pool water back to sanitary conditions and this process takes 1-3 days or up to a week depending on the condition of your pool

We hope we can help you inform sufficiently about algae in your pool and how to clean it. 

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