The Ultimate Guide on How to Clean a Green Pool

Is your swimming pool turning green? It must be nasty, right? But, do not worry! You have come to the right place as you will be able to know how to clean a green pool effectively here. Keep scrolling and enjoy reading!

Why Does My Pool Turn Green?

Everybody loves swimming in a clear blue pool. It looks refreshing, appealing, and inviting. Unfortunately, it can turn into green sometimes, which seems dirty and nasty. No one would want to dive into it.

Have you sometimes questioned why your swimming pool is discoloring? More importantly, do you know how to clean a green pool in 24 hours? Let’s find out the answers.


One of the most ubiquitous culprits when it comes to a green pool is algae. They are aquatic organisms that contain chlorophyll, hence the color.

Since algae have chlorophyll, they can conduct photosynthesis. However, they lack true stems, leaves, roots, and vascular tissue.

But the problem is that algae grow rapidly. You will even notice cloudiness in your swimming pool before you finally see the hints of green.

The rapid growth of algae occurs due to improper pH balance. Too low pH level may cause eye irritation and erode pool materials.

On the other hand, if it is too high, it can irritate your skin and will not be able to kill algae and bacteria.

A clogged filter is also another thing that is responsible for water discoloration. If it happens, algae will continue growing and bacteria will breed.

If you live in a warm area, you will be likely to experience water discoloration. It happens because algae thrive well in a warm and humid environment.

Therefore, if the weather becomes warmer, you have to find a way of how to clean a green pool as soon as possible.

You cannot end this problem by simply draining the pool because you have not eradicated the main culprit yet. If you cannot control algae, the water will soon turn green again. Therefore, you will need chlorine.

Yes, chlorine is the answer. In addition, the chlorine will help you control algae in your pool.

Another problem that you will face when algae have invaded the water is the mosquitoes and also other insects. Therefore, it is imperative to know how to clean a green pool.


In addition to algae, pollen can also make the water in your pool look green or yellow. You might be wondering how it happens.

Nearby plants and trees produce pollen. Later, the breeze moves it to the pool water. As a result, you will notice water discoloration.

Since the size of the pollen is too small, standard pool filters cannot remove them well. Eventually, it will continue to build up throughout the year and begin to stay on the liner.

Once the pollen builds up and settles on the liner, you might think it is green or mustard algae. Fortunately, it is not harmful to you and the water.

But if you are seeking a way of how to clean a green pool from pollen, you can use a fine-mesh skimmer net.

This skimmer will help you collect very fine particles, and thus it can pick up pollen well.


Besides algae and pollen, metals (especially copper) can also be the cause of water discoloration.

You can find metals from many sources, such as the source of water, acidic water, cheap algaecides, or from the metal components found in the pool like copper heater elements.

Unlike pollen that will not cause any harm to the water, metals can make the water green. Eventually, they will stain the pool for good.

If you have blonde hair, you will also find your hair turn green when swimming in the water containing metals.

What Do I Need to Keep the Water in My Pool Clear?

Swimming in a clear pool can be fun. To make this idea tangible, ensure your pool is at the following state:

  • Appropriate chlorine level. As you know that algae are one of the most common things that make your pool green and cloudy. Therefore, you need to keep chlorine in the water to stay at its appropriate level. The Association of Pool and Spa Professionals states that free chlorine levels should be between 2.0 and 4.0 ppm.
  • Correct pH. To gain clear pool water, the pH level should stay between 7.4 and 7.6. If you want to shock your pool, make sure that the pH is between 7.2 and 7.6. Too high pH will lead to cloudiness.
  • Appropriate alkalinity. The proper range of alkalinity can help you maintain the pH and chlorine levels more easily.

How Much Chlorine Do I Need to Keep the Algae at Bay?

You have learned the importance of chlorine when it comes to keeping your pool clear. It can help you get rid of algae – the culprit that turns the water green and cloudy.

However, you might be wondering how much chlorine you should add to the water and how to clean a green pool with it. The amount of this substance will depend on the size of the pool and the algae that grow in it.

If you want to shock your pool, you may need to pour in more than a 2.5-gallon bottle of chlorine into the water. You can also go with several pounds of granules.

To acquire the most solid performance, you must grasp the appropriate amount of chlorine you need. You can begin by calculating the volume of liquid that your pool sustains.

Once you know how much it is, read on the chlorine packaging thoroughly.

How to Clean a Green Pool Properly

Presently, it is the opportunity to discover how to clean a green pool properly. This process entails checking the pH balance of the water, shocking the pool, pumping and filtering the water, adding flocculent, and eliminate algae. So, let’s get started!

1. Drain or Not to Drain?

The first thing you need to do is to decide whether you should drain your pool or not. It depends on the color of the liquid.

If the water is dark green and creates a border on a blackish color, it means you may need to drain the pool and acid wash the surface.

However, if you can still see at least six inches under the water surface, you do not have to drain it. Treating it chemically would be enough.

2. Lower the pH Level

You learn how to clean a green pool is by shocking it. But before doing it, you may want to lower the pH level of your pool. First, you need to test it with a testing kit for liquid chemistry.

A pool has a healthy pH level if it is around 7.5. Since you are going to shock it, you need to lower it until it reaches below 7.2 by using sodium bisulfate.

If your pool is too green, you do not need to test the pH level because the chlorine level is already too low.

3. Time to Shock the Pool

Once you have lowered the pH level of your pool already, it is time for you to shock it with granular chlorine (calcium hypochlorite).

Shocking the pool means you add a super shock liquid chlorine. This way, you can instantly eradicate most bacteria and algae.

Once the bacteria and algae are dead, consider de-structuring the algae DNA by chlorinating the water to 30 ppm. If you are not sure, you can use a testing kit to know the right balance.

4. Pump and Filter the Water

After shocking the pool, you need to pump and filter the water so that you can regain balance. You may also need to consider backwashing the filter to remove any dirt and sediment.

Here is how to clean a green pool filter thoroughly:

  1. Shut the pump off, and then roll out the backwash hose. After that, check the waste line to find any closed valves.
  2. Turn the handle to the backwash. Or, you can also try to slide the push-pull valve.
  3. Turn on the pump and the water will flow out the backwash pipe or hose.
  4. Backwash the pipe for at least 3 minutes until the liquid is apparent.
  5. Turn off the pump.
  6. After that, turn the valve back to filter.
  7. Lastly, turn on the filter.

5. Add Flocculent

After pumping and filtering the water, you will probably find that the water is a little cloudy due to the leftover residue of microscopic particles of bacteria, dirt, and other substances.

Relax! It is not dangerous or whatsoever. You can overcome this problem by adding flocculent.

Adding a flocculent will cause the ruins to bundle. This way, you can vacuum the bottom of the pool more easily, allowing you to get crystal clear water.

Besides, adding flocculent also helps you remove pollen.

6. Get Rid of the Algae

Now, you know all the steps of how to clean a green pool, and you have succeeded in eradicating most algae in the water. However, you still need to consider this additional step.

Algae grow extremely fast. They can even take over your swimming pool from just a few minute spores. For this reason, you need a good algaecide that can kill the remaining microscopic spores while holding them at bay.

You may also notice some debris and leftover at the bottom of the pool. But, worry not, because you can use a skimmer to scoop them up.

If the debris is still there, you should call a pool technician to get some help. Therefore, you can save the life of your filter.

How to Clean a Green Pool with Bleach

Is there another way of how to clean a green pool? Sure, there is. You can as well as do it with bleach.

Bleach contains sodium hypochlorite – the same chemical that you can find in chlorine – with different concentrations.

The one in chlorine is between 10 to 15 percent. However, the one in bleach is only 5 to 6 percent. Therefore, you will need more bleach as a way of how to clean a green pool.

How to clean a green pool effectively with bleach requires good timing. Since chlorine degrades in sunlight quickly, it would be better for you to add the bleach in the late afternoon or even in the evening so that it has more time to work in the dark.

Below are some ways on how to clean a green pool with bleach:

  1. Test the pH balance of your pool and lower it between 7.2 and 7.8.
  2. Get your test kit and check whether the level of cyanuric acid is between 20 and 50 ppm.
  3. Now, here comes the math. Measure your pool’s volume by multiplying the width by the length. After that, multiply it again by the average water depth. Next, figure out how much bleach you will need. For example, one gallon will increase the free chlorine level of 30,000 gallons of water by 2 ppm. If you need to raise it more, you will need more gallons of bleach.
  4. Pour the bleach along the edge of the pool in the late afternoon or early evening.

The Pool Maintenance

Ways on how to clean a green pool are not that complicated. Once the water is clear, you need to do thorough maintenance so that the algae will not come back soon.

Here are some simple things you can do to maintain your pool:

  • Check your filters and pumps regularly for any algae debris.
  • Scrub your pool surface and vacuum the bottom religiously to keep the algae and bacteria at bay.
  • Maintain the right pH level between 7.4 and 7.6.
  • Consider using a pool cover to prevent any pollen from making a mess in your pool. It also helps you suppress the growth of algae because they will not get full sun.

Now, you know how to clean a green pool and maintain it to be crystal clear. Happy trying and good luck!

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