Phone Number

(281) 252-6337

Email Address


Magnolia, TX

32403 FM 2978 Suite 118,
Magnolia, TX 77354

It’s bad enough when you discover green algae in your pool – who wants to swim in that? But what about if you find black algae in your pool? Well, in this post, we’ll address the issue of black algae forming in your pool and talk about how you can get rid of it.

First of all, if you’ve found black algae in your pool, don’t swim in it until it’s treated!

What is Algae? Where Does It Come From?

Algae is the name for a vast and diverse species of aquatic plants. Essentially, they live in the water and use sunlight via photosynthesis for energy. This makes them similar to many other plants, all of which have chlorophyll – the substance that gives them their green color. However, what’s interesting is how they feed and reproduce, as this tells us about how they get into your pool in the first place.

Algae, like any other organism, need food to survive. Luckily, though, they can feed on pretty much any speck of debris that floats into your pool. Any dead cellular matter can feed algae. They’re present in small amounts in any pool water, even the clearest and cleanest, but are not harmful to swimmers. Instead, they wait patiently for the opportunity to explode in population. If you don’t run your pump for long enough or clean your filter regularly, they seize the chance and start to grow, seemingly overnight! Low chlorine levels and a rise in pH also trigger their growth. As for how they reproduce: the wind can carry algae spores over long distances right into your pool water.

However, black algae are very different from green algae. How? Well, first of all, they’re not algae at all…

Black Algae Are Actually Bacteria, And May Be Harmful

Specifically, black algae are cyanobacteria. This means that they have pigments aside from the green chlorophyll that allows them to photosynthesize. They’re also notoriously difficult to get rid of! Worse still, cyanobacteria like black algae can produce cyanotoxins, which can make you, your family, and your pets very sick.

And where do they come from? It’s very simple: contamination from a natural body of water or someone who has used contaminated pool equipment in your pool. If someone forgot to thoroughly wash and clean their swimwear or swimming gear before getting into your pool, that’s likely why you now have black algae.
It’s crucial, therefore, to act on black algae as soon as you spot it in your pool. Black algae shows the following characteristics:

  • It’s difficult to scrape off, and the stains they leave behind can’t be scraped off at all.
  • The black clusters or spots have raised bumps or heads and are attached firmly to the pool’s interior surfaces, not just floating in the water.

To use your pool safely and healthily, it’s essential to deal with the algae thoroughly. This is especially difficult since even if there are no visible clumps of algae, the bacteria are microscopic and only need the right conditions to grow again.

The Takeaway

Dealing with black algae requires a thorough cleaning of the filter, pool water testing, brushing, and scrubbing. Multiple passes of brushing and scrubbing are necessary, and you may need to “shock” your pool many times as well. Throughout the process, you’ll need to keep an eye on any new growths and raise chlorine to very high levels in the water. Algaecide and other special chemicals are required, with levels measured out precisely for the dimensions and volume of your pool.

Learning how to do it yourself is a great way to get ahead of any pool infestations, but for best results and to save time, you should contact an experienced professional.

At Town and Country Pools of Texas, we pride ourselves on our 45+ years of experience in the business of outdoor leisure. We know what pool products are best and know how to maintain your equipment for maximum enjoyment. If you have any questions about your pool, please give us a call at (281) 252-6337.

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