Pool Black Algae: Remove from the Pool in 7 Steps

The common black algae are the worst type of algae that can develop in a pool. If it catches you, you should not panic right away. But why is it the worst kind?

After all, there are still the yellow mustards in pools and even the normal green algae can sometimes be quite annoying in swimming pools.

The black algae like to grow in cracks and form deep roots, which meander into the material. Chlorine is not always helpful in this case, because algae are naturally immune to all forms of this chemical.

For this reason, one must not be squeamish when it comes to removing evil. Especially the dark sides of the pool will be infested, which you do not recognize immediately.

Before cleaning black algae, search all areas and treat them as many places as possible in one pass. Tetra pond debris handling pump can be helpful in cleaning this.

How to remove black algae (instructions)

In order to remove all black algae completely and thus effectively from the pool, you need a high-quality pool brush in any case. This is, so to speak, our primary weapon when it comes to removing black algae.

When it comes to a pool with concrete or plaster walls, then a pool brush with steel bristles is recommended. If you own a vinyl pool, you should tend towards nylon bristles so that the surface of the pool is not damaged.

#1 Disinfection

To defeat the black algae, it is not enough to clean only the affected areas in the pool. So that she does not smile at us again a few weeks later, you have to start with the basics.

Everything about toys, accessories, but also your own swimwear and any items that have had contact with the pool water must be thoroughly washed and disinfected. This is not just any hint or step to skip for convenience.

When it comes to swimwear, the procedure is as follows: A wash cycle in the washing machine can usually be enough to minimize the greatest danger. As for the items, you do the following: Take some bleach and wipe everything with it.

Before that, however, you should clean the air mattress, mobile phone case, and all other things with a suitable brush and use surfactants in any case.

#2 Pool Chemistry

Since you should check the pool water regularly anyway to ensure crystal clear water quality, this point falls into the “routine category” of many pool owners anyway.

For the plan to work, the water should have a pH between 7.2 and 7.6. In addition, it is also important to bring the alkalinity to a value, which should be somewhere in the range between 80 and 150 ppm.

If the values deviate too much, it could be that the removal of the black algae does not work. This is mainly due to the fact that, for example, some pool chockers only work properly under certain circumstances.

#3 Brushes

Now comes the fun part, because you can use the power you have trained over the years in the studio meaningfully. If you prefer to sit at the PC instead and have not trained any strength, simply call a friend for help.

The next step is to brush the pool as if there were no tomorrow! Only by vigorously brushing off the walls and the floor, you can get the annoying little roots out of the cracks.

#4 Shock chlorination

In the best case, you should perform quadruple chlorination when you are done brushing. You have to think of it roughly like brushing your teeth: When you’re done, mouthwash is a successful conclusion.

In order for everything to work, you can always carry out the shock chlorinations only after sunset. The reason is that the sun would change the pool chemistry and the pool chocker would just burn instead of doing something about the algae.

At this point, nature works together and there is no choice but to wait. When you are finished, you should leave the sand filter system on for about a day or two. After the water treatment, it should run 24/7 until the algae have completely disappeared from the water.

Only if not a single one of the black algae can be seen, you should switch the filter time back to 8 hours.

#5 Re-brushing

That’s what you’re looking forward to the most because now you can prove again how strong you are. After several days of preparation including carbohydrate-rich meals, you are now well prepared for the task and can brush off the pool walls again like a world champion.

The most important thing is not to treat the cracks too squeamishly, but to reach as deep as possible with the brush tips.

It is also advantageous to remember the places with the greatest infestation. These places should also be scrubbed more thoroughly after the optical removal than the other spots.

#6 Re-shock chlorination

If the deed is done, you should of course continue to run the sand filter system 24/7. In addition, new shock chlorination is announced, which is ideally carried out about 3 days later. The dosage does not need to be increased this time.

#7 Continuous care and brushing

The following days will be full of action, so you can already look forward to it. From time to time you should brush off the corresponding areas until the algae have completely disappeared. During this time, you have to keep a closer eye on the pool than you usually do. If you see new vegetation, then you have to get the pool chocker and the pool brush out of the garage again.

Tips for avoiding & eliminating algae

The best tip is that you should be careful not to bring any black algae into the pool water. But that’s so easy to say. Often your own family adheres to all the rules, but the neighbours could also have the pathogen on the swimwear. Diy pond pump can also be a good choice.

If you put on your swimwear from your holiday, for example, you could even carry an exotic type of algae. If the algae light up colourfully and are fluffy and soft, then you can simply leave it in the water as if the pool were an aquarium.

But joking aside, advise everyone who enters your pool that they should have washed their swimwear at least once in the washing machine before they are allowed into your water.

#1 Keep pool chemistry in the green on an ongoing basis

So that the unwanted algae guests do not settle in the first place, you should counteract with healthy water quality in advance.

Pool maintenance is, therefore, an important factor so that the water remains clear and not green. Every week you have to check the water with a test strip or pool tester and best of all keep a book. The following values are significant:

  • Alkalinity
  • pH
  • Chlorine

#2 Keep pool accessories and equipment clean

The pool kescher is not only there for amusement and should therefore not only be used to pull someone into the water with it. It must also be used continuously for pool maintenance.

Branches and leaves fall into the water from time to time and the small microbes organize their colonies. A pool robot could be very useful if it is a larger pool.


If you carry out shock chlorination once a week, you do not even have to worry about the black algae settling in your pool.

As already mentioned, shock chlorination should only be carried out after dusk so that the effect is as good as possible. Black algae put you to the test, but if you are harder, scrub stubbornly and perform your shock chlorinations, then you can defeat the black algae and the water becomes crystal clear again.

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