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Things That You Have To Know About Black Spots In Pool


If you are a meticulous pool owner, you want all the areas of your pool to be sparkling clean and clear! You may also periodically notice black spots in your pool, but they are not algae. Black spots in pool not algae can be caused by stains, and may still be dependent on the type of pool you have.

These black spots in pool not algae can also be seen along the grout of bathroom tiles, and may also grow in the silicon seams of showers. When seen in pools, these can be difficult to get rid of, but there are ways that we can start doing so, and causes can also be identified to avoid these black spots from ruining the pool floors and walls. Let us have a more detailed discussion, below.

Black Spots

Part 1. Getting To Know Black Spots

At first glance, you would think that these black spots along the areas of your pool are black algae, but they aren’t. These black spots can be seen in dark green color sometimes blue; they are called black spots since it features a dark spot usually seen at the top part of the grown area. This dark spot is the only part of the algae that is seen, and which tends to grow reaching areas of your pool. The reason why it can be harder to get rid of is, that it likes to grow on areas that are called shady such as pipework, filtration, or pump systems.

Some think that removing the head of the black spot is enough, however, it will only return in just a few days due to the many layers of it used against chlorine. It is somewhat classified as a slow-growing type of algae that can be hard to remove once it has established its habitat in some of your pool parts. Even if you have emptied your pool, it can still survive, and may even grow more once the water has been refilled.

Different reasons can cause these black spots not algae in pool. Of course, one of the major causes is high phosphate levels and poor chlorination. These black spots can feed on the phosphates, so they can grow more. On the contrary, even if there is a low phosphate level in the water these black spots not algae can still survive. Well, you have to make sure that your pool water chemistry is always monitored, and that you have adequate chlorination all the time. For you to be familiar with other possible causes of black spots, these are:

  1. If there is foliage near your pool.
  2. If you have low chlorine levels most of the time.
  3. You have consistently high pH, and you do nothing about it.
  4. If your pool has old and worn-out interiors.

You may be wondering if it is still possible to get rid of black spots in pool not algae, since aside from being not aesthetically pleasing, it is also not clean to have it in your pools.

Black spots are said to be difficult to remove from pools, well when it comes to anything, prevention would be a better choice than learning to cure it! You just have to ensure that your pool is well chlorinated, you can also start by always checking chemical levels and maintaining chlorine levels at 1.5 ppm. You also have to check if chlorine is well distributed in your pool waters and to do it, you just have to keep water circulation working well. Furthermore, you can also start by running your water pump for 8 to 12 hours a day, and all seasons while maintaining the required pH level which is in the range between 7.4 and 7.8 ppm, and total alkalinity at the range between 80 and 120 ppm.

Pool Level

It is also a must to remove all the debris that you see in your pools and maintain its cleanliness all the time. You can vacuum at regular schedules to prevent any type of algae from growing and do not forget to include the cleanliness of other pool equipment such as ladders, diving boards, steps, slides, pool cover, and pool toys.

Part 2. What Are Some Tips To Get Rid Of Black Spot?

In case your pool has already black spots on it, there are still plenty of things that you can do to remove them. Below, we have listed some of the tips that you can start doing in case your pool is already infested with black spots.

1. Brush Your Pool’s Floors and Walls.

You have to make sure that you use a bristled brush in cleaning the surfaces of your pool. You should include all the around fixtures and difficult corners. Not only that, you have to brush so hard to break the membrane of the black spot, and also remove the spores to stop it from growing further.

Brush Black Spots in Pool

2. Always Check Your Water Chemistry.

When it comes to pools, water chemistry is the driver. It is a must to do frequent checking of different chemical levels and have these maintained all the time.

3. Do Vacuuming and Pool Cleaning.

The secret to a clean and clear pool is a responsible owner who always like to check up on the pool itself. You should always vacuum your pool to remove all the debris, and check your filter, it is possible that black spots are in there, and you have to remove all the black spots and residues that you will see.

4. Shock Your Pool As Often As Needed.

It is a must to shock your pool once you see that black spots are already building up. At the first time, you have to use three times more than the amount of your normal shock dosage. Execute it at night, and start running your filter system for 24 hours until you have noticed that the black spots are already removed. Then after a few days start shocking your pool once more, and this time just use the normal amount of pool shock that you usually use for your pool.

Pool Chlorine Granules

5. Check and Clean the Filter.

Once you see that there are black spots around your pool, this means that they can be present in your pool’s filter as well. If your pool uses a sand filter or DE, you have to do backwashing and then make sure to rinse your filter many times. If your pool has a cartridge filter, you can remove the cartridge and wash it off.

6. Always Clean Your Pool’s Equipment.

You have to sanitize all the items that you are using in your pool such as pool toys, equipment, bathing suits, and floats as well. You can use a specified cleaner to do it.

These are only some of the tips that you can try one by one in case you already noticed the formation of black spots around your pool. It is always better to do something at first glance before anything gets worse. Alternatively, you can always ask some pool professionals if you think that the growth of black spots is already too excessive and you can’t control the growth anymore. This is more applicable to pools that are already left behind for years or months, in which algae and bacteria growth is already too intense.

Part 3. FAQs

1. Is Black Algae Harmful to Bathers?

Black algae can’t hurt you! You also won’t get sick from swimming in pools that have algae on them, however as time goes by and it is not treated, it can cause the growth of bacteria which is not a good thing for the bathers and the pool itself. So, once you see the formation of it along your pool, do something to get rid of it!

2. Are Black Algae Different from Green Algae?

Yes, they are different from each other, however, both were types of algae. Black algae are harder to remove compared to green algae. Black algae have really deep roots, it also have a protective layer that protects them from chemicals used in treatments to get rid of them.

3. Is There a Recommended Time to Shock My Pool if There are Black Algae on it?

If you want to get rid of black algae faster, do pool shocking, it is the ultimate black algae killer! Use additional doses of your regular pool shocking dose to clear black algae. You must perform the shocking at night or in the evening so that the rays of the sun won’t affect the chlorine added to the pool especially if you have an uncovered pool.

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