What Does Black Algae Look Like in a Pool & How to Remove?

There are various types of Algae growing in the swimming pools. Among them, Black Algae is the most ardent one. If your pool is still safe from Black Algae, you need to know what does black algae look like in a pool.

Are you tired of scouring for the ideal way of removing Black Algae? I’ve got your back. Besides introducing yourself with a 6-step removal method, you need to be acquainted with the characteristics of it. So The next time, it won’t seem a threat to you. 

Before explaining the removal process, let’s tell you what Black Algae is!

What is Black Algae?

Black Algae is a single-celled organism that is visible when formed in coin size. Some people also refer to it as blue-green algae. Like many other algae types, they consist of chlorophyll. The root develops in the cracks of cement.

As the body of the algae has several, protective lairs, eradicating it from the root isn’t a piece of cake. Unlike the other type of Algae, Black Algae is more resistant to Chlorine. As a result, eradicating it using Chlorine isn’t that easy.  

Black Algae usually finds its way through natural water resources, or if your dog bathes in your pool. Dog fur is a good medium for these figures to find their way to your swimming pool. If someone swims in a lake or river and comes to your pool, there are chances of algae attacking your pool. 

What Does Black Algae Look Like in a Pool?

If you have a swimming pool or thinking of constructing one, knowing the appearance of a Black Algae is a must. Because once Black Algae attacks your pool, you’ll have to bite off more than you chew. So, let’s tell you about how Black Algae looks-

  • Greenish-Blue or Black floats near the wall or concrete area of the pool. Unlike other types of Algae, Black Algae doesn’t flow.
  • Coarse patches or spots in the corner of your pool’s plaster. They tend to attach to something to grow.
  • Other Algae bodies come off easily. A bit of Chlorine removes them. But Black Algae will not come out within a second. 
  • Black Algae spoils the natural shine and color of your pool. You may assume it is a random mineral stain. Black Algae doesn’t come off, even after scratching it hard. 
  • It has a mold-like texture. 

How to Remove Black Algae from a pool?

Getting rid of Black Algae is not a piece of cake. As it’s resistant to Chlorine, you can’t get rid of it using any chemical substance. And shocking the pool won’t work out as well. Even though pool shock plays a part while removing the Algae. But you’ll have to scrub the Algae hard for it. And don’t forget to backwash the filter. 

Here’s the detail of the removal process- 

  1. If you have a sand filter, rinse it off after backwashing it. And for removable cartridges, you need to bring them out and wash them using a garden hose. 
  1. Bring out a coarse-bristled brush to rub the Algae growing around your pool’s ladder, liner, or anywhere. Rubbing it hard won’t eradicate the Algae. But it will destroy the coating above it which has been protecting it. Once you’re done rubbing it off using the brush, take out a pair of rubber gloves. Then rub the spots again with a Chlorine tablet. 
  1. Take thrice the amount of Sodium Dichlor pool shock that you generally use. As the packet suggests a pound for 10,000 gallons of water, use 3 pounds for the same amount of water. And for light-colored pools, sprinkle a bit of Granular Chlorine on the surface around the spots. But make sure that you don’t do it in dark-colored pools. The bleach might discolor the pool surface. 
  1. Add an Algaecide to your pool water. Follow the instructions for assuring that you put the right amount.
  1. For dark-colored pools I recommend you turn on the filter immediately. Otherwise, the bleach will spoil the color of the pool. And for light-colored pools, let the filter go off for some hours. Once you turn on the filter, let it run for 24-48 hours. 
  1. Even after all this if you still see spots, redo the whole process all again. But use normal dosage this time. And run the filter for some extra 24 hours this time. Once you elevate the Chlorine levels of pool water, don’t forget to brush the pool surface for 2 to 3 days. 

How to prevent Black Algae from growing in your pool? 

You’re a lucky guy if you’ve still managed to safeguard your pool area from Black Algae. But the safety isn’t long-lasting if the prevention method isn’t worth it. As prevention is better than cure, you should know the process. So, I am going to write down below the process of preventing Black Algae.

  • Always rinse and dry your swimming costume after swimming in natural water resources.
  • Be sure that the Chlorine levels, pH, and Alkaline are at a safe level.
  • Run your pump for 8-12 hours every day. It will filter off even the tiniest spore.
  • Tidy up your pool tools and toys once a week.
  • Give your pool a heavy shock treatment regularly.

Incentives that Execute Black Algae Growth

Dirty and Polluted water is a friendly environment for Black Algae. If your pool’s filter isn’t working well, it won’t clear up the water in it. And that can enhance the growth of Black Algae. If such a situation occurs, you can’t control the issue even after using chemicals. Running a proper filtration system or using bug-free motors is a condition of having a Black Algae free pool


Keeping your pool tidy and germ-free is a bit of a hassle. But it’s worth every moment if you know the correct process. This article will work wonders for you, if you want to know what does Black Algae looks like in a pool I have done all the research and hard work on the article to ensure your satisfaction. If you’re a newbie in the pool cleaning process, this article is going to be your best friend.

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