How To Clear Green Pool Water In 5 Steps

How To Clear Green Pool Water In 5 Steps

Anthony Barnes

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It may have been a long time since you thought about having a swim in your pool.

How To Clear Green Pool Water In 5 Steps

Yet, when you decide that the weather is right to take a dip, you have noticed that the water in your swimming pool’s water looks a lot greener than you last remembered. 

You shouldn’t swim in green water as it isn’t safe. Thus, you need to clear the water as soon as you can, otherwise the problem will get worse.

Green water is something that happens to a lot of people. 

In this article, we will be discussing how you can clear your green pool water in 5 easy steps. 

Why Has Your Swimming Pool Turned Green?

Algae (see also ‘The 7 Best Pool Vacuum Algae Reviews‘) is one of the most common causes of green pool water.

When algae grows in your pool, it produces an acid which turns the water green.

Algae is known as a very simple plant that loves to be in the water. 

However, it is easy for algae to get into your pool water.

This is because algae is actually airborne or can be transported into your pool by attaching itself to a pool toy or someone’s swimsuit.

Immediately once the algae enters the water it will eat all the phosphorus and nitrogen and then the green color can start to appear in your water overnight. 

The shade of the green color can vary from light to dark green.

Although, the shade of green of the pool water can help give you an insight into who you are going to fight the algae in your water. 

Why Does Algae Enter Your Pool?

It can be annoying when you see algae starting to taint your pool water. This is usually because of the lack of sanitizer and testing of the water.

If your swimming pool’s chlorine and sanitizer levels fall below too low, or your chlorine is mixed with other chemicals that are present in your swimming pool.

This is a breeding ground for algae. 

As long as you have good levels of sanitizer in your swimming pool, this will make the water inhospitable to the algae.

This will then kill any algae present in the pool’s water. 

Alongside this, you need to make sure that you are regularly testing your pool’s water (see also ‘The Best Pool Water Test Kits‘).

If you don’t add enough sanitizer, such as chlorine or bromine, then your chances of algae developing are increased the longer the levels are kept so low.

If you test as often as you can, then you should be able to keep the algae at bay. However, sometimes that doesn’t always work out. 

Sometimes it may mean you need to test the water more regularly.

Or even extra tests overall, as these other tests could make the chances of algae increase.

Other factors that can lead to algae growing in your swimming pool water includes: 

  • Extreme weather changes and temperature changes.
  • High Wind.
  • Your swimming pool is dirty with debris – Debris is a great food source for algae.
  • The pool filter has stopped working and is clogged.
  • The pH levels are wrong. 

If you do notice any of these situations happening in your pool, then the chances of algae forming are increased.

Thus, this is when you need to test your swimming pool a lot more often.

We would suggest that in these situations, you may want to test your pool’s water every day or even every other day to just be safe. 

Turning Green Water Clear

Step 1: Draining The Pool

Ideally, no one really wants to drain their pool if they can help it.

However, you need to decide whether you need to drain your pool, depending on the shade of green that your pool water is. 

You need to decide on how green the water is.

A lot of experts have found that if you can see around 8 inches into the water, then you shouldn’t need to drain your swimming pool.

Although, if you can’t see that far, then the chances are you will need to drain the pool.

Step 1: Draining The Pool

Then, after all the water has been drained out, you acid wash the pool to deeply clean it and rid it of algae. 

However, you can try to clear the water of its greenness first, before you decide to drain it and give it an acid wash.

Also, it is worth checking your filters at this stage too and giving them a good clean as well. 

Step 2: Test Your Pool’s pH Levels

At this stage, you need to check the sanitizer levels.

However, if your pool is green then we know that the levels are far too low, because that is why the pool has turned green in the first place. 

However, you still need to test the pH levels of the water as well. There are lots of kits available that are easy to get hold of.

There are also kits that help to restore the pH of your water too.

You must balance the pH levels of your pool water. If you don’t balance the levels, then you could be left with really cloudy water instead of clear.

It is known that sometimes you can for short periods of time deal with cloudy water, however after being filtered the water shouldn’t remain cloudy for very long. 

There are pH chemicals available that have been produced to adjust the pH levels of your pool water.

These chemicals are able to balance the levels. You should aim for around 7.2 or below on the pH scale. 

Step 3: Shock Your Pool

When we say shock your pool, what we mean is that you need to add a lot of chlorine to it.

By adding a huge amount of this sanitizer, you are making sure that you are really destroying all the algae that is present in your pool’s water. 

You should be aiming to add 30 parts per million of liquid chlorine to your pool’s water. We understand that this sounds like a lot.

However, this amount is the right amount that can break into the algae’s nucleus and stops it from trying to reproduce.

In simple terms, it kills the algae completely. 

Either use If you use 10 gallons of liquid chlorine or if you have  a diatomaceous earth filter, we would suggest using 5 pounds of granular shock.

Step 4: Let Your Filter Do Its Job

You have now shocked your pool’s water, and removed all traces of algae from the water.

However, now you need to let your chosen filter on your swimming pool do its job.

Anything that has been left in the pool’s water will be filtered out by your pool filter.

We would suggest that you allow your filter to clean the water several times, until the water becomes crystal clear. 

If you use a diatomaceous earth filter, then you will have to backwash the filter and add a new filter before you start this filtration process. 

Aim to let the filter run for around 24 hours after you have added all the chlorine and the pH chemicals.

Your water should be running really clear after 24 hours.

This is the time when you can wash the pool to make sure it is clean and wash the filter again and let the filter run for another 24 hours.

After this second 24 hours, the water should be running a lot clearer. 

Step 5: Adding Algaecide And Flocculant

You may want to consider adding an algaecide to help this process along. An algaecide actually helps to kill any algae present in your pool water.

Also, you may want to add a flocculant, this will help the filtration process as it brunches all the dead algae together.

These two chemicals should be added a couple of hours into the first filtration process. 

Some people don’t use this final step, but if you want to make sure you haven’t missed any of the algae, then it is worth adding them. 

Final Thoughts

No one likes opening up their pool and seeing green water. The culprit is algae that has had a chance to breed in your pool’s water.

The best way to keep on top of algae is constant testing.

The more you test, the more you can stay on top of decreasing the chances of your pool water turning green. 

In this article, we have given you all the tips on how to clear your green water. Therefore, the next time your pool turns green, you know what to do. 

Thank you for reading!

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By Anthony Barnes

Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age