How Long After Shocking Your Pool can you Swim?

Shocking your pool is such an effective way to remove algae, bacteria, and other harmful contaminants. It’s quick and results are seen as sudden as overnight. While it works really fast, we need to be sure the pool is safe to swim in after adding shock to your pool.

After shocking your pool with a chlorine-based shock, you should wait until chlorine levels are under 5ppm which takes about 24 hours. Swimming in water with high chlorine causes itchy eyes and rash. Swallowing this water can cause nausea, vomiting, difficulty breathing, and chest pain.

Every time you add any chemicals to your pool, it is always recommended that you allow the chemicals to dilute and for the water to balance before you jump in! Let’s look at the suggested waiting period for other treatments.

How Long Should I Wait Before Swimming After Adding Chemicals to my Pool?

You should always wait for your pool water to balance and for the chemicals to dilute before you allow anyone to swim in your pool. Some chemicals that require you to wait before swimming are:

Chemical AddedTime to wait
1. Calcium Chloride (Water Softener) 4 Hours
2. Algaecide 15- 30 Minutes
3. Flocculant 24 Hours
4. Chlorine 4 Hours
5. Soda Ash or Bicarbonate of Soda 1 Hour
4. Muriatic Acid 30 Minutes
5. Cyanuric Acid 0 (Swim Immediately)

1. How long should I wait after adding Calcium Chloride before swimming?

Calcium Chloride is used to soften swimming pool water that has high calcium hardness. Calcium Hardness is the amount of dissolved calcium and magnesium that is in the water. High calcium hardness is harmless to humans but can be damaging to your pool finish and equipment.

You should wait 4 hours after adding Calcium Chloride to the pool water before swimming. Calcium Chloride can cause irritated skin, and even a rash is severe cases. It can also cause severe irritation in the eyes.

I do not really recommend Calcium Chloride to soften water. Most pool water that is too hard can really only be balanced by diluting the water or completely replacing it.

Read more about calcium harness in my previous article What is Calcium Hardness in Pool Water?

2. How long should I wait after adding Agaecide before swimming?

Algaecide is specifically designed to kill algae in your swimming pool, along with other micro-organisms such as bacteria, fungus, and germs.

You should wait at least 15 to 30 minutes to swim after adding algaecide. Swimming immediately after adding algaecide can cause irritation of the skin and eyes.

If you have a serious algae problem, read my article on how you can fix your green algae infested pool overnight.

3. How long should I wait after adding Flocculant before swimming?

Flocculant is used to bind solids in water so that they form heavier particles. These will settle at the bottom of the pool so that you can vacuum them out.

You should wait 24 hours to swim after adding flocculant. You need to vacuum the flocculant out from the bottom of the pool before swimming. Swimming in your pool after adding flocculant will prevent it from doing its job. The pool water needs to be still for the flocculant to work properly.

4. How long should I wait after adding chlorine before swimming?

Chlorine should be added as often as necessary in order to maintain Chlorine levels of 1 to 3ppm (parts per million). Chlorine is essential in sanitizing your water keeping it safe to swim in.

You should wait 4 hours after adding chlorine before swimming. As an extra safety measure, use a test strip to make sure the chlorine level in the pool is less than 5ppm.

You really should be testing your water regularly anyway. If not, read my article How Often Should I Test My Swimming Pool Water? to help you draw up a testing routine.

5. How long should I wait after adding Soda Ash or Bicarbonate of Soda before swimming?

Soda ash and Bicarbonate of Soda (AKA Baking Soda) is used to raise the pH or Alkalinity in pool water. The fact that you have needed to add one of these, means the water was too acidic.

You should wait at least an hour after adding Bicarbonate of Soda or Soda ash before swimming, allowing the pool water to balance. Use a test strip to make sure the pH levels are between 7.2 and 7.8 before swimming.

It’s worth mentioning that Soda Ash will increase both the swimming pools water Alkalinity and the pH, while Bicarbonate of Soda (Baking Soda) will raise the Alkalinity independently without affecting the pH.

This is handy when the total alkalinity of the pool is low, but the pH is correct.

4. How long should I wait after adding Muriatic Acid before swimming?

Muriatic acid is ACID, and it is used to lower the alkalinity or pH of your pool water. The muriatic acid you pour into your pool will not mix and dilute immediately. There will be “hot spots” of acid floating in certain areas of your pool where there is slow circulation.

You should wait at least 30 minutes after adding muriatic acid before swimming to allow the chemical to mix and dilute properly. Be sure to test the pH of the water before swimming, it should be between 7.2 and 7.8.

Exposure to high levels of muriatic acid can cause burns on the eyes, skin, nasal passage, and throat. Exposure to high levels of Muriatic Acid can cause respiratory tract irritation and inflammation which can affect breathing.

5. How long should I wait after adding Cyanuric Acid before swimming?

Cyanuric acid is also known as a stabilizer. It’s the main purpose to protect the chlorine in your pool from UV damage by the sun. Cyanuric acid levels should be between 30 and 50ppm.

You can swim immediately after adding cyanuric acid to your pool. Cyanuric acid has a very low level of toxicity with very little health concerns.

Read The Effects of Cyanuric Acid and How to Manage It.


We have all been kids once, and we know how eager they get to swim when the summer is upon us. But we are responsible that our pools are safe to swim in.

Unbalanced water can cause some nasty side effects.
Chemically unbalanced water can cause pretty severe side effects to our swimmers. These include minor things like red eyes and rashes, but also include more serious ailments such as respiratory tract inflammation, nausea, difficulty breathing, and even acid burns!

So we really need to make sure our pool water is well balanced, sanitized, and strictly implement waiting times after adding new chemicals despite the temper tantrums from our brats.

Implement a waiting period after adding chemicals.
So after adding shock to our pool, we should wait at least 24 hours until we open the pool for swimming. In addition to that, we should wait 4 hours after adding Calcium Chloride or Chlorine, 15 to 30 minutes after adding Algaecide, 24 hours after adding Flocculant, one hour after adding Soda Ash or Bicarbonate of Soda, and 30 minutes after adding muriatic acid.

It might be a good idea to add chemicals at night when you know for sure that the pool won’t be used.

Always test before swimming after adding chemicals.
In addition to implementing a waiting period after adding chemicals, we should always test the water before the kids can jump in! Use a test strip to make sure Chlorine leaves are between 1 and 3ppm, and under no circumstances higher that 5ppn. pH should be between 7.2 and 7.8 at all times.

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