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How to Prevent and Eliminate Pool Algae

September 12, 2022

pool floor with black algae

When you see pool algae forming, you want to act fast — algae looks unpleasant, can pose health risks and damage pool equipment, not to mention it’s a slimy substance you don’t want to slip on. Let’s dive into learning how to get rid of algae in a pool and how you can prevent future outbreaks.

What Is Pool Algae?

The word “algae” describes a large group of organisms that are mostly aquatic, such as seaweed and other single-celled forms that contain chlorophyll, but lack leaves, roots, stems and vascular tissue. In a pool, algae can be free-floating or stick to your pool walls and appear green, black, yellow, brown or red. It can make the water look cloudy, and particular forms can rapidly spread throughout your pool, especially on hot, sunny days during the summer.

Fortunately, pool algae are treatable, and you can prevent the organisms from reappearing with a pool maintenance schedule.

Causes of Algae in a Pool

Commonly, algae spores come from plant debris and soil, traveling from your yard and into your pool via wind, rain, contaminated pool equipment or even you and the kids. If your children often play in the yard before hopping in the pool, they can track spores into the water if they don’t rinse off beforehand. Plus, using the same items you use in the ocean or a lake in your pool can lead to the presence of algae.

There are four factors that cause the algae to bloom and spread when the conditions are right:

  1. Poor circulation
  2. An imbalanced pH level
  3. Poor sanitation
  4. An ineffective filtration system

Without water movement, algae can grow and quickly spread. An imbalanced pH level could also cause a bloom. This means your pool chemicals aren’t at the correct levels, causing poor sanitation. Finally, a poor filtration system that doesn’t circulate the pool water can cause an algae bloom.

These four factors in addition to harsh or direct sunlight are the perfect recipe for algae blooms, meaning ongoing pool maintenance is critical.

pool tile with green algae

Types of Pool Algae

Knowing which type of algae is lingering in your pool can help you troubleshoot the issue. For example, will it require a quick scrub and consistent filtration or a quadruple shock of chlorine? Different types of pool algae include green, yellow and black.

In some cases, you may also see a pinkish color form in your pool called pink mold or slime. While not a type of algae, pink mold is a form of bacteria that can spread in small spots and the corners of your pool. It spreads more slowly, so using algaecide to get rid of it will typically do the trick.

Green Algae

This variety of algae is the most common type and results from poor water circulation and filtration. Often found in the corners of a pool, green algae can spread quickly and cause the water to look cloudy. While green algae are free-floating, they can also cling to the pool’s wall in large sheets. Fortunately, green algae are the easiest to kill, which is why regular cleaning is key to keeping your pool clear.

Yellow Algae

Also known as mustard algae because of its yellow-brown color, yellow algae commonly form in shaded areas of the pool that have limited circulation, clinging to the walls and floors. Thriving in humid climates, yellow algae can look like clumps of pollen.

This kind of algae is often resistant to typical chlorine pool levels and re-infection is common, so shock treatments are the best solution. This means adding copious amounts of chlorine at once — the more serious the algae, the more shock necessary. Shocking super-chlorinates the pool water, making it easier for you to filter out the dead algae and kill the spores.

Black Algae

This version of algae is the most resistant type of algae and can form on your pool’s floor, walls, cracks and equipment. These algae are often found in concrete setups and may appear dark green or blue. Additionally, black algae are smaller in size compared to green and yellow algae, usually the size of a quarter or smaller. Using a strong granular chlorine shock can help get rid of the issue.

How Long Does It Take for Pool Algae to Go Away?

When you notice algae forming in your pool, it’s best to act fast to prevent further spreading. There are 10 steps you can take to get rid of pool algae:

  1. Identify the type of algae.
  2. Remove everything from the pool.
  3. Manually vacuum the existing algae and other debris.
  4. Scrub the pool with a pool brush to kill algae spores on the walls, steps and ladder.
  5. Test the water’s pH level and alkalinity.
  6. Add pH or alkalinity to balance the levels.
  7. Conduct a concentrated chlorine shock treatment.
  8. Filter out dead algae.
  9. Test the pool water again.
  10. Clean the pool filter.

The different algae types require different levels of shock:

  • Green: Double shock
  • Yellow: Triple shock
  • Black: Quadruple shock

It’s best to shock your pool in the evening or at night because sunlight can eat away at the chlorine faster than it can do its job. Run the filter throughout the night, as well.

After following the above steps, your pool should clear up in about one day. To ensure all the algae is filtered out of the system, make sure to consistently run the pump to circulate the water. However, depending on the level of shock you used, it can take a bit longer. If your pool doesn’t clear after several days, consulting a professional can help.

How to Prevent Pool Algae From Forming

Having a maintenance schedule in place will help keep your pool clean. Some parts of a proper algae preventative maintenance schedule include keeping the water balanced, having a clean filtration system, rinsing swimwear and toys and ensuring consistent water circulation.

Here are a few steps to consider:

  • Check and balance chemicals and pH levels once per week or after heavy use.
  • Make sure the filtration system is working, cleaning it often.
  • Scrub the pool walls on a daily basis to prevent algae blooms.
  • Use the pool frequently for constant water circulation.
  • Cover the pool when not in use.
  • Use algaecides to kill early algae growth.
  • Wash pool equipment and toys, especially after you use them in other bodies of water.
  • Close the pool at the appropriate time each year.

Another way to protect your pool from algae blooms is to install a swimming pool safety cover. These safety covers keep your pool free of dirt, leaves, pollen, sticks and other debris that attract and help algae bloom. Specifically, winter covers help maintain your pool water until you’re ready to reopen it in the spring.

Prevent Pool Algae With Tools From SPQ Brands

Enjoy your summer days at the pool by maintaining it with the right tools. SPQ Brands manufactures pool products like vacuums, brushes and covers to ensure your pool water stays clean throughout the year, even after you’ve closed it down for the season.

Reach out to an SPQ Brands representative to learn more about how our tools can help you maintain your pool water and get rid of existing algae blooms.

pool floor being vacuumed