how to get rid of black algae swimming pool

Key Takeaways:

  • Algae growth, particularly black algae, is a common issue for pool owners in Las Vegas.
  • Black algae are resilient and difficult to eradicate due to their root system.
  • Poor filtration, warm water, unbalanced pH levels, and neglected maintenance contribute to black algae growth.

How to Get Rid of Black Algae:

  • Brushing: Use a stiff-bristled brush to scrub off black algae, starting from the shallow end and moving to the deep end.
  • Shock Treatment: Apply a shock treatment that is 3-4 times stronger than regular chlorine doses evenly across affected areas. Run the pool circulation system for at least 24 hours.
  • Algaecide Treatment: Use an algaecide, either copper-based or non-copper-based, to eliminate remaining algae. Ensure proper filtration afterward.

Preventing Black Algae Growth:

  • Regular Brushing: Brush the pool walls and floor at least once a week to prevent algae buildup.
  • Proper Chemical Balance: Test and adjust pH, alkalinity, and chlorine levels regularly.
  • Regular Water Circulation: Run pool pumps and filters continuously to maintain proper water circulation.
  • Cleaning Pool Equipment: Clean and dry pool toys, floats, and accessories regularly to prevent algae growth.
  • Proper Pool Maintenance: Schedule professional pool cleaning services regularly to prevent and remove black algae growth.


Fighting algae is an inevitable reality for swimming pool owners, as their pools create new aquatic environments. Despite their artificial appearance, swimming pools can become breeding grounds for algae, which can quickly spread and surprise owners.

As a responsible pool owner, it is important to be aware of this risk and understand the need to address it. Maintaining the correct pool chemistry is essential for effectively eliminating many types of algae. Among the various algae types, black algae pose the greatest challenge to eradicate. Therefore, leveraging available resources becomes imperative in the battle against black algae.

What is Black Algae?

When attempting to understand the nature of black algae, it is crucial to consider the varying colors of algae. Algae, in a manner of speaking, appears to be color-coded for ease of identification. Eliminating green algae, a more common occurrence than black algae, is relatively straightforward.

Black algae, on the other hand, is less prevalent, which is undoubtedly advantageous. However, it poses greater challenges in terms of detection and eradication. Noticeable black algae spores and small patches may be observed on the surface of pools. While algaecide may effectively eliminate many algae blooms, it is often insufficient for combating a black algae bloom.

Black algae have demonstrated a remarkable survival strategy. They infiltrate pool plaster and exploit existing cracks, establishing firm root systems. Consequently, cleaning and eradicating black algae become significantly more arduous.

Causes of Black Algae in your Swimming Pool

Black algae (it’s actually blue-green algae, but we’ll refer to it as black algae) can be difficult to eradicate because it grows roots that attach themselves to surfaces. This means that simply shocking your pool with chemicals won’t work. There are multiple reasons why black algae grow in swimming pools. The most common causes are:

  • Poor filtration: When your pool filter isn’t working correctly, it’s allowing debris to accumulate in your pool and giving the algae extra nutrients to grow.
  • Warm Water: Black algae thrive in warmer water, so it’s important to keep your pool water cool.
  • Unbalanced pH Levels: When your pool pH levels are too high, it creates a good environment for algae growth.
  • Neglected Pool Maintenance: When a pool is not properly maintained, it becomes a breeding ground for black algae.

How to Get Rid of Black Algae

In order to effectively combat black algae, it is crucial to adopt a proactive approach. Let’s begin by utilizing algaecide, a pool pole and brush, gloves, and chlorine tablets. Concentrate your efforts on targeting the black algae using a chlorine tablet, or alternatively, a clip with an attached chlorine tablet can serve the purpose just as effectively. Keep in mind that during brushing, a cloud may arise, indicating progress. For a duration of approximately twenty-four hours, it is necessary to deactivate the filters and pool pumps. Following this, add the recommended amount of algaecide to the deeper end of the swimming pool. This will induce an imbalance in the water chemistry, an aspect of utmost importance to consider. The objective is to establish optimal pool chemistry levels and pH, which is inherent to the process. For about a week after treating the black algae, refrain from swimming in the pool.

Safeguarding against the emergence of black algae primarily revolves around maintaining proper pool chemistry. Effective pool filtration and circulation serve as preventive measures to combat various issues. Keep in mind that while it may be feasible to eliminate black algae independently, seeking assistance from pool professionals may prove necessary for severe black algae infestations.

Brush it off

Start by scrubbing off the black algae with a stiff-bristled brush, working from the shallow end of the pool to the deep end. Be patient, as it may take a while to remove the algae entirely. Avoid using nylon brushes as they can scratch the pool’s surface. Instead, opt for a steel brush and cover your hands with gloves to avoid scratches.

Shock treatment

To ensure the black algae is completely dead, use a shock treatment. The shock treatment should be 3-4 times stronger than regular doses of chlorine and spread evenly across the affected areas. Keep the pool circulation system running for at least 24 hours to guarantee the complete removal of black algae.

Algaecide Treatment

Once you have brushed and shocked your pool, it’s time to use an algaecide to keep it clean. Algaecides come in two categories: Copper-based and non-copper-based. Copper-based treatments eliminate algae pretty fast, but it may react with your pool’s water chemistry. Non-copper-based algaecides take time to work, but their efficiency is long-lasting.


After the shock treatment and algaecide treatment, your pool may appear cloudy. This is because of the dead algae and other organic materials that the system will catch. Clean or backwash your pool’s filter to remove the dead algae and improve filtration.

Preventing Black Algae Growth

Regular Brushing

If you’re serious about preventing black algae, then brush your pool regularly. I know this sounds obvious, but it’s the most critical step in algae prevention. Black algae forms a strong bond with surfaces, so the only way to remove it is by brushing. It’s recommended to brush at least once a week. Start by brushing the walls and then move to the floor. Remember to pay extra attention to those hard-to-reach corners and crevices where algae loves to hide.

Proper Chemical Balance

Chemical balance plays a significant role in keeping algae out of your pool. When the pool water pH, alkalinity, and chlorine levels are off, it becomes easier for algae to grow. Maintaining a proper chemical balance is a crucial part of preventing algae growth. To do this, test the water regularly and adjust the chemical levels accordingly.

Regular Water Circulation

Another essential step is keeping the water moving through proper circulation. Proper water circulation ensures that all areas are well-distributed with chemicals, and stagnant water is not left to allow algae to form. Run the pool pumps and filters around the clock for the best results. Proper circulation will ensure that chemicals are distributed properly to prevent the growth of black algae.

Cleaning Pool Equipment

The pool equipment is the breeding ground of algae. This includes pool toys, floats, and accessories you use in the pool. The equipment should be cleaned and dried regularly to prevent algae growth. Any equipment that is not being used should also be kept clean and dry. Over time, algae can build up on the equipment, leading to the growth and spread throughout the pool.

Proper Pool Maintenance

Pool maintenance is very crucial in preventing and removing black algae. Regularly scheduling professional pool cleaning services can help prevent the growth of black algae. These professionals are well-equipped to remove any black algae growing in your pool, and they can provide a deep clean to make sure the chances of black algae coming back are minimized. A professional pool cleaning service can also advise you on any necessary upgrades that may be needed to make your pool a safer environment.

Call a Professional

If you’re having trouble getting rid of black algae in your pool, don’t hesitate to reach out to professionals. They have the expertise and tools to get the job done efficiently and quickly.


Black algae are a common problem in swimming pools, but with the right information and precautions, you can keep your pool algae-free. Remember to conduct regular pool maintenance, use the right chemicals, and pay attention to the signs of black algae growth. In the end, a clean and clear pool is the perfect way to enjoy those hot summer days!


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