How to Get Algae Off Bottom of Pool

Last updated Oct 10, 2021

Posted in Swimming Pools & Spas

While having a pool is amazing, cleaning it can be difficult and time-consuming. And I’m not talking about the dirt and stains that can accumulate at the bottom of the pool. I’m talking about algae. This problem is not easily solved by sanitizers or bleach. You’re going to need more power and time.

Thankfully, experts revealed some of the best techniques to get rid of algae and keep them from growing on your pool for good. First, let’s look at the different kinds of algae that can infest your pool so you can better understand how to get rid of them.

Types of algae that can infest your pool

Without proper care, algae spores from the air can easily go into the pool. Once they establish at the bottom of the pool, they start to colonize on its surface and become unstoppable. When spotting algae at the bottom of your pool, there are several types of algae you need to watch out for.

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Green algae

Green algae are the most common type of algae that can grow at the bottom of your pool. These have a slimy texture that can also suspend themselves in the water, making the pool appear green. In severe cases, the algae can saturate the pool to the point where people can no longer see the pool floor, much less the steps. This usually happens during the summer and they can colonize the entire pool in as fast as 24 hours.

Yellow algae

Also known as mustard algae, this type of algae is a type of green algae, but with a different texture and appearance. This has a yellow-brown color that looks like dirt accumulated at the bottom of your pool. Yellow alga is a much stronger form of green algae because it is immune to highly sanitized and highly chlorinated environments. Even if you can brush yellow algae to remove it, these can easily grow within hours.

Pink algae

The term pink algae, on the other hand, actually a misnomer because this is not a type of algae. It’s a type of bacteria. The color pink comes from the pigment present in its cells and the slime that surrounds it protects the bacteria from external threats.

Pink algae can grow anywhere in your pool but sometimes it can grow along with white water mold. It also tends to grow in PVC pipes or anywhere direct sunlight cannot reach. According to researchers, pink algae are common in pool areas that do not receive at least 6 hours of sun exposure. It can also be caused by the bacteria brought by rainwater.

Black algae

The last but not the least type of algae is black algae. It is the most difficult to remove once it forms on the pool surface. Unfortunately, it’s also difficult to spot at its early colonizing phase. Most people only spot algae when it’s already a size of a fingernail. By that time, it will already be difficult to remove and it will start to grow rapidly.

According to some studies, black algae can easily grow on tough plaster, probably because of the calcium buildup. This alga can dig a root into the porous surface of the pool, usually between the plaster and the concrete. From there, it starts to establish a strong and unstoppable colony. Even if people try to remove the visible portion of the algae, the roots are still embedded on the plaster and it could easily grow and spread.

As you can see, there are different types of algae that can grow on your pool’s surface. Some are harder to eliminate than others. This is why you need to identify the algae present in your pool to understand which methods are effective in eliminating them.

How to get algae off the bottom of the pool

No matter how often you check and clean your pool, algae infestation is inevitable. These are strong and resilient organisms that thrive in water. So, when you see algae on your pool, don’t be too hard on yourself. You can just eliminate it using the following steps:

Step 1: Clean your filter

The first technique you can use to eliminate algae is to check your filter and clean it. Because this tool is responsible for eliminating dirt from your pool, it could also be the source of algae buildup.

This is one of the most vital steps before cleaning or brushing the pool’s surface. There’s no use cleaning the pool if the source of the algae infestation is not addressed. Depending on the type of filter you have, you can either backwash it or hose down its cartridge to eliminate the accumulated algae colony before cleaning the pool.

Step 2: Check the water level

If you own a pool, you probably already know that the ideal pH level of pools should be around 7.2 to 7.6. If it goes beyond or below this level, you might need to add some chemicals to achieve the ideal pH level. Although this method may not be enough to eliminate some types of algae because they are immune to sanitation and chlorine, it can probably help control weaker algae types and keep them from spreading.

Step 3: Brush the pool

Brushing the pool’s surface once or twice is essential to eliminate all kinds of algae. However, if you’re dealing with black algae, you may want to use more aggressive methods because of its protective layers. Some even use aggressive chemicals while brushing the pool more than twice. This way, they can penetrate the roots of the black algae that’s allowing them to reproduce quickly.

Step 4: Shock the pool

The next step is to shock the pool. This is one of the most effective ways to eliminate all kinds of algae, including black algae. Since these are considered a part of the plant family, these organisms can die by shocking them using calcium hypochlorite. If you plan on doing this, make sure to follow the instructions of the manufacturer to avoid overdoing it. Using too much dichlor could cause too much acidity on the pool, which inhibits the sanitizer from penetrating the pool water.

Another tip you can keep in mind when shocking the pool is to do it at night. According to experts, the heat of the sun can burn off the chlorine liquid shock before it could take effect. So, it’s best to start shocking the pool at dusk to give the chemicals some time to kill the algae before you start cleaning the pool.

Step 5: Add algaecide

After 24 hours of shocking the pool, it’s time to add algaecide and allow it to circulate for another 24 hours. From the term itself, algaecide is a special solution that kills all types of algae. And because you already shocked the pool with calcium hypochlorite, most of the algae will already be dead and the rest is already too weak to withstand the algaecide. So, adding this chemical after the shock is the most effective way to kill all the algae in your pool for good.

Step 6: Brush the pool

24 hours after you added the algaecide, it’s time to brush your pool again. During this phase, you can observe that it’s easier to remove the accumulated algae in your pool be it green, yellow, pink, or black algae. Remember to vigorously brush all the surfaces of the pool, including the floor, the sides, the steps, even the handles. You can never be too sure when it comes to algae, so you need to make sure you cover every surface of your swimming pool.

Step 7: Vacuum the pool

After brushing, you need to vacuum the pool using a reliable tool. This way, you can eliminate the dead algae along with leaves and loose debris. Just like the previous step, it’s important to cover every surface of the pool to make sure no dirt is left. For best results, experts recommend vacuuming the pool several times to make sure that it’s clean and free of algae.

Step 8: Test the water

After these methods, you need to test the pool water’s pH level the next day to ensure that it’s still within 7.2 to 7.6. If not, consider shocking the pool again after a couple of days to reach the ideal pH. If not, you could add some pH correctors to help your pool achieve its ideal alkalinity.

Step 9: Run the filter

The last but not the least step is to run the filter until the water is clear. This usually takes 24 to 48 hours, depending on the accumulated dirt on your pool. After you’ve accomplished all of these steps, you can see that your pool looks good as new. Now, you can enjoy swimming with your friends and family.

A Friendly reminder

As we said before, algae infestation is an inevitable phenomenon. After cleaning, it’s important to keep some strategies in mind to help keep algae infestations at bay.

  1. Check the water’s pH balance regularly.
  2. Shock the pool weekly and apply algaecide.
  3. Always check that the filtration system is functioning.
  4. Brush the pool regularly.
  5. Lastly, regularly vacuum the pool.

With these techniques, you can prevent algae infestations and maintain a clean and presentable pool to use. Remember, if you cannot do these processes all by yourself, you can always seek help from service providers. This way, they can ensure the effective and safe application of chemicals and treatments.

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