How Long After Adding Algaecide Can You Swim

Everyone wants their pool to be neat and clean. But that’s not the case every time. Maybe you just had a pool party or your pool got out of chemistry, or maybe some random guy forgot to wash his swimsuit and decided to have a splash in your pool. In cases like this having a kind of greenish and cloudy pool filled with algae is pretty normal. It comes free with pool ownership.

But you surely wouldn’t want to keep your pool like this right? You want your pool to look like transparent glass again. Adding a little bit of algaecide might get the job done. But how long after adding algaecide can you swim?

In this article, I’m going to talk about exactly that. You’ll get all the information you need about the usage of algaecide and what’s the exact time you need to wait before using your pool again for swimming. But first, we need to know what algaecide is and how it works.

How Long After Adding Algaecide Can You Swim

Different Types of Algae

There are different kinds of algae that affect your pool. Each of them occurs different kinds of problems. Following are a few of these algae’s.

  • Black algae: This kind of algae comes to your pool if someone mistakenly enters there without cleaning their swimsuit properly after taking a bath in places that have a natural water source. Like ocean or lake or river. A little bit of cautiousness can solve this issue.
  • Green algae: This is probably the most common algae of them all. You can easily locate it for its green color and can be seen in most of the pools. The reason behind this algae attack is not having a proper sanitation system. If the filtration process isn’t done properly then the number of algae will increase too. And there’s also a possibility of the pH of the pool getting high if this happens.
  • Yellow algae: This kind of algae is also known as mustard algae and can be found in southern climates. It’s probably not what you’ll find in your pool. It is chlorine resistant and is another form of green algae.

How long do you have to wait to re-use your pool after adding algaecide

Algae can make your pool look dirty and unappealing. But good use of algaecide can ensure that your pool is back to good as new in no time. So knowing how much algaecide you have to use or how long you have to wait until you can swim again in your pool is always helpful.

Usually, 20-30 minutes is considered safe before going back to the pool again.

But if someone goes a little before that there’s no need to panic. No unfortunate case has been recorded for jumping a little bit ahead of due time but it is always advised to wait until 20-30 minutes before using the pool again.

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How algaecide functions

Algaecide is mainly made from copper. There are two kinds of copper algaecides. Copper sulfate and copper chelates. These things are chemical compounds and use metal as their central atom.

But there are also other kinds of algaecides available in the market. This kind of algaecides uses either herbicide endothall or sodium carbonate peroxyhydrate. These chemicals help to disrupt the regular cell processing system of algae. But it’s still unknown to us how this process is completed.

There isn’t any clear explanation of how this process is completed. Perhaps the cell division or energy transport is disrupted or the synthesis process of new cell proteins is destroyed. We all know how vital that is for the cells to survive. Algaecide works to some extent, there’s no confusion about that. But it is unclear how it works.

Another thing that needs to be kept in mind is that if you are working in an area that has a high amount of metal elements in its waters then adding copper-based algaecides is probably not the best idea. Because adding more copper to areas like this only increases the possibility of oxidation. And as a result, you’ll get stained pools. We surely wouldn’t want that to happen.

Now that we know how algaecide functions it’s time to figure out when to add algaecide and how long you have to wait after applying algaecide so you can use your pool again.

When to apply algaecide in your pool

Algaecides’ best use is to kill all the algae from your pool which are affecting the quality of it. If it’s not done properly then there’s always a possibility of getting water bugs, infections, irritants.

And there’s also a chance of your pool damaging its surface. So using algaecide is always a good idea if you want to prevent algae in your pool. It won’t change the pH balance of your pool but stop algae from growing.

It is always advised to apply algaecide after each shock treatment.  By doing this it’ll work better with the chlorine. And when the chlorine level reach backs to normal level add the right amount of algaecide. Do not add too much or too little as it might hamper the process altogether.

Add it to different parts of your pool and keep the pump running. This will help algaecide spread all over the pool.

One thing should be pointed out that using shock treatment and algaecide together can create a terrible chemical reaction if necessary steps aren’t taken before. It is highly recommended to leave the pool for at least 24 hours after shocking it. Then apply algaecide.

Also, you should be aware of the amount of algaecide you are applying. This amount depends on your pool’s water holding capacity. If the amount is not right and you add too much algaecide it’ll form a foam that might do some good amount of damage to the filters.

This could also lead to skin and eye irritation. Dark and humid weather is algae’s best friend. So do not forget to add algaecide while closing down the pool for the year.


What is the difference between chlorine and shock?

Chlorine is a sanitizer. It is used to maintain pools’ clean state. On the other hand, shock is chlorine but in a high dose and it’s meant to shock your pool. It is also used to increase the chlorine level quickly.

If I have algae what should I do?

If any kind of algae is seen growing into pools’ walls you could brush it off. But if it’s visible in water the best possible solution might be using some algaecide. First shock your pool to increase chlorine level then use an algaecide to get rid of the problem.

How long do I have to wait to use my pool again after using chemicals of any sort?

Jumping straight into the pool after adding algaecide or any kind of other chemicals is never advised. You should always wait for about 20-30 minutes before you can get into your pool again.


Nobody wants a dirty pool filled with algae. But with a little bit of cautiousness and knowledge, you can easily get rid of these problems. Follow the steps mentioned above and wait for a sufficient amount of time before jumping back to your pool again.

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