How to Remove Black Algae From Your Pool


Black algae may seem harmless but they can cause damages to your pool, so they aren’t ones you should ignore. It won’t be easy to get rid of them because they build their community in the smallest spaces and cracks that people don’t usually notice, but it is doable nonetheless.

But before we get into the process on how to remove black algae from pool, it is important to know where algae come from and how they look like, as well as some ways to prevent them from appearing in the first place.

Black Algae and Why They Form

Black algae are not rare to find in swimming pools, but they don’t appear just because they want to appear; they appear for a reason. Reasons like, maybe you haven’t cleaned your pool since two months ago, or maybe your pool is located beside a beach and there’s someone who has brought algae from the beach to the pool.

The list goes on, but the point is, black algae are organisms that are transferred from one place to another, and most likely by humans.

Black algae are not necessarily black in color. Most of them are greenish, just like other algae, and that’s because of their chlorophyll content.

Nonetheless, unlike other algae, they are more difficult to remove from pools because they aren’t scared of chlorine. Especially if they already have established their community there, it would take you lots of work to get rid of them.

How to Remove Black Algae from Pool

Characteristics of Black Algae

Apart from the fact that black algae are not naturally black, here are other characteristics of black algae that you should know.

1. Black Algae Are Bacteria

And not really algae. Algae are organisms that are found in bodies of water. They are plants, so they are not harmful in any way. But black algae, as they are bacteria in nature, can be harmful in some way.

If your pool acquires a huge amount of black algae, it can be dangerous. Black algae are toxic because of their being cyanobacteria. Cyanobacteria release cyanotoxins, and cyanotoxins, apparently, are poisonous.

If one insists to swim despite of the presence of black algae, that person can become sick. Water infected with black algae can cause stomach aches and can even damage the liver, if accidentally consumed.

2. Black Algae Are More Common in Pools Made From Porous Materials

Porous materials include concrete and plaster, so if your pool is made from either of them, you should be more watchful of your pool. We don’t suggest that you keep an eye 24 hours a day—that’s impossible! But you should clean it more regularly so as to avoid black algae from growing their roots in between small spaces available.

3. Black Algae Don’t Float

Black algae are not like those leaves floating on the water that you can just remove with a rake. They are attached to hard surfaces, so it is important that you go deep into your pool, observe, and find small dark spots on the walls, floors, or stairs.

How Can You Remove Black Algae From Pool?

Black algae may be easy to be spotted, but they are not easy to remove. Even if you use the most abrasive brush you have, black algae don’t stay on the surface. They grow roots, and the roots are what make them reappear every single time.

If you want to remove black algae from pool, and I mean really remove them for good, there’s a way, and that’s what we’re going to talk about here. Here’s a simple step-by-step guide that even the beginners can do.

How to Remove Black Algae from Pool

1. Brush the Infected Area

There are lots of pool brushes available, but the best one to use in this case is a brush that’s specifically for algae. Algae brushes are made with bristles that can remove even the roots, or at least most of them, planted by black algae.

Just brush the infected area thoroughly and make sure that you don’t miss even the narrowest space there is.

2. Use Chlorine Tablets to Kill Black Algae

When you think you’ve removed the black algae from the infected area, use chlorine tablets to kill them. Black algae are bacteria, and bacteria are not seen by the naked eye, so it’s advisable that you don’t just focus on the area itself but also the areas surrounding that area.

Also make sure that you rub chlorine tablets on the surface where the black algae were once attached to. This can help remove the roots that were not removed by the brush.

3. Check Your Pool Filter

Your pool filter’s role is important because it maintains you pools cleanliness, which is why if it is not working well, black algae are most likely to find there new home in your pool. Check if your pool filter functions properly. If it’s not, have it fixed!

4. Clean Your Pool Equipment

Black algae spread, and they can even spread up to your pool equipment. Having said that, you shouldn’t just focus on making your pool water free of black algae; you should also find time to make sure that the equipment are disinfected.

5. Shock Your Pool

Black algae don’t limit themselves, and they love spreading and making their community much bigger! While it’s a great thing to want to have a bigger community, having too much black algae in your pool is not at all good.

Not all black algae are contained in one space. Some of them go to different areas of the pool, so pool shock is necessary.

6. Add Algaecide

Sometimes, a mere pool shock is not enough. Algaecide can prevent the black algae from coming back.

7. Reach Out to Professional Pool Cleaners

If your pool has become so infected that you can’t treat it by yourself anymore, you can always ask professional pool cleaners to do the job for you. Professional pool cleaners are trained, and therefore, they know what to do.

If you’re in the Houston area, you can call us! We would be very happy to serve you!

Black Algae Can Be Prevented

Black algae are a headache to deal with. However, who says that you have to meet them face to face? Black algae can be prevented, and it’s actually much better if you choose to prevent them because it would save you more time! Just imagine how much of your time it would take to brush off black algae and their stubborn roots.

If you wish to prevent black algae, here are simple ways to do so.

  1. Brush your pools’ walls and floors regularly.
  2. If your pool is located beside a beach or ocean, ask the swimmers to wash themselves first before they swim in the pool.
  3. Make sure your pool pump and filter are doing their job well.
  4. Sanitize your pool equipment every week.
  5. Shock your pool regularly.

In one sentence, to avoid black algae, you have to make sure that you do pool maintenance on a regular basis. Even if the swimmers go back and forth the beach and your pool, you can still prevent black algae if you take care of your pool.

Taking care of your pool is not actually something that should be seen as an “added” responsibility because the moment you decide to have a pool, you should already have considered the fact that you will really have to lend time to make sure that your pool is safe and free of bacteria.

You shouldn’t have thought of acquiring a pool in the first place if you don’t like even the idea of pool maintenance.

How to Remove Black Algae from Pool


Black algae are never pool owners’ best friend because they are very damaging, not just to the pool itself but also to human health. Black algae may sound harmless because of the “algae” in its name. However, black algae are not actually algae in nature. They are cyanobacteria that release cyanotoxins, which are harmful!

It is possible to prevent black algae from appearing. Just make sure that your pool is clean and that you maintain it regularly and that’s it. However, even if that seems an easy job, not all pool owners have the time or the interest to do pool maintenance every week, or even every month.

As a result, black algae become happy because they found a new home⁠—and that’s that pool owner’s pool.

That’s frustrating, and those lazy pool owners only realize that when their pools are now infected with black algae. Black algae can be removed, though, but it would take more work than when you give your pool the attention and love it needs.

There are lots of ways to remove black algae from pool, but if there are things that are common to all of them, they are as follows:

  1. Brush the infected area.
  2. Use chlorine tablets to kill black algae.
  3. Check if your pool filter is still working well.
  4. Clean your pool equipment.
  5. Shock your pool.
  6. Add algaecide.

But even if you follow the steps, it’s still not sure if you have really gotten rid of the black algae because bacteria, given that they are microscopic, can go to different areas and can grow their roots anywhere without you even knowing! And that’s why between treating them and preventing them, the latter is a much better choice.

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