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How Long to Wait After Shocking a Hot Tub (before using)?

By: Author Jeff Campbell

Posted on  - Last updated:

Categories Hot Tub Health Tips, Hot Tub Water Chemistry

Shocking a hot tub is necessary to keep your water clean and your sanitizer effective. But you can’t just get in immediately after adding hit tub shock, so you may have wondered how long to wait after shocking a hot tub.

Ideally, wait for 24 hours after applying a chlorine-based shock. However, 15-20 minutes is sufficient when using non-chlorine-based shock. In both scenarios, run the jets and leave the lid off, restarting the jets as needed for the first 20 minutes. 

But there’s a lot more to know.

In this article, we’ll find out if you can put too much shock and how quickly hot tub shock works. We’ll also discover if hot tub owners can get into a hot tub faster using non-chlorine-based shock.

Let’s get going.

Ready to Spend Less Time On Maintenance and More Time Enjoying Your Hot Tub?

Let’s face it. Balancing the water, cleaning filters, dealing with rashes, and trying to figure out which chemicals to buy and add can make you feel more like a chemist than someone who just wants to relax after a long hard day!

That’s exactly why The Hot Tub Handbook and Video Course is so valuable!

This is from Matt over at Swim University and he developed it for people looking to save money, time, and frustration. His tips on chemicals can save you $100/year just by making sure you buy only what you need.

So if you’re ready to stop being confused or frustrated with your hot tub and start spending more time in it, check out The Hot Tub Handbook and Video Course.

Just click that link to learn more on their website.

how long to wait lg

Do you have to wait 24 hours after shocking a hot tub?

You don’t have to wait for 24 hours after shocking a hot tub if you apply a non-chlorine-based shock. In fact, 15-20 minutes after its application, you can soak in the hot tub.

However, if you applied a chlorine-based shock, ideally wait for twenty-four hours.

But ultimately, the 24-hour recommended waiting time is to help us to avoid entering a hot tub where the chlorine levels are too high.

After 20 minutes, it’s okay to dip a test strip in to see what the levels are and see if you have safe chlorine levels. However, this still depends on how much sanitizer or shock is added and where the levels were before adding it.

The difference in the time you have to wait is because both shocks have different consistencies and work slightly differently.

Chlorine-based shocks are more concentrated and more effective. They are slow-acting, and because of the high concentration of chlorine, they can irritate the eyes, skin, and lungs. Naturally, you wait for a longer time before you get to soak.

Non-chlorine-based shocks, on the other hand, are fast-acting but not as effective because they do not eliminate algae and bacteria. But they have no effect on pH, leave no residue or odor, you get to use the tub faster.

So, do you have to use a non-chlorine-based shock if you use bromine? 

Check out a recent article I published. I get into whether it’s okay to use a chlorine-based shock if you’re currently using bromine as a sanitizer and the differences between shocks and sanitizers. But I also shared the difference between chlorine and non-chlorine-based shocks.

Just click the link to read it on my site.

Can you put too much shock in a hot tub?

Yes. It is possible to put too much shock in a hot tub. When it occurs, it is not the end of the world. But avoid soaking for 24-48 hours until the levels on a test strip are normal. If the levels are really high, also consider partially draining the tub and topping it off with fresh water from the hose.

Putting too much shock can be detrimental to your body and the hot tub.

When you’ve used too much, it could trigger skin and lung irritation. So, you always want to wait for the suggested time, test the water, ensure the chemical levels are okay and that the chemistry is balanced before you soak.

There are two main causes of over-shocking:

1. Too-much chlorine:

Before you shock your hot tub, you want to confirm your chlorine level, by testing the water. If it’s too much, and you went ahead to add shock, you’ll probably apply too much. You’ll need to wait much longer before you can use the tub.

Interested in knowing more about whether it’s safe to go into a hot tub with high chlorine? This is what I explored in a recent article I published.

In it, I explained if you could go into a hot tub with high chlorine and what happens if the chlorine level is too high in a hot tub. But I also revealed what you could do if the chlorine level is too high.

Just click the link to read it on my site.

2. Shocking too often:

Ideally, you shock the hot tub once a week or every other week if you use it sparingly. If the hot tub is used a lot or by many people, you could shock it twice a week.

But note that the more frequently you shock it, the more you run the risk of over-shocking it.

How quickly does hot tub shock work?

Chlorine-based shock is highly concentrated and slow-acting and could take up to 24-hours before fully activated. Non-chlorine-based shock, on the other hand, works a lot faster in about twenty minutes.

Then always test the water again before getting in.

Make sure you run the jets and leave the lid off, restarting the jets as needed for the 1st 20 minutes either way. Say you applied chlorine shock to a hot tub that has been heavily infested with algae. You may need more than 24 hours before it effectively does its work.

In some cases, it could take up to 48 hours.

But the vital thing is that whether you applied chlorine or non-chlorine-based shock, you test the water before using the hot tub. It’s something one has to do after sanitizing or oxidizing a hot tub.

Can I get in a hot tub faster if I use non-chlorine shock?

Yes. You can get in a hot tub faster if you use non-chlorine shock. Twenty minutes after shocking the hot tub, you can test the water to ensure that its chemistry is balanced, after which you can soak in the hot tub. 

However, you would need to wait for twenty-four hours if you applied chlorine shock instead.

Non-chlorine shock offers certain advantages over chlorine-based shocks, and it’s a couple of these that makes it feasible that you can use the hot tub faster. Chlorine-based shocks come with the strong unpleasant chlorine smell we’re all too familiar with. And folks with sensitive skin may find the water that has been oxidized with chlorine shock harsh.

The strong chlorine smell is not a good sign and not a sign that the hot tub is being maintained well. It’s actually a red flag. Non-chlorine shock, on the other hand, does not have the chlorine smell (which is actually the odor of chloramines).

And it is mild on the skin. But like most things, it has its cons. So, you get to soak faster, but it lowers the pH of the water, does not really sterilize the water, and does not remove combined chlorine (chloramines).

Suppose you’ve just refilled your hot tub; do you need to shock it? 

Check out a recent article where I get into it. I explained when is the ideal time to shock your hot tub and the chemicals you need after you’ve refilled your hot tub. But I also revealed what shocking a hot tub does.

Just click the link to read it on my site.

How quickly does liquid shock work in a hot tub?

Liquid spa shock works quickly. It starts dissolving in the hot tub water immediately because it is already in liquid form.

Before you apply it, remove the hot tub’s cover and check the pH level. Leave the cover open for 20 minutes afterward. Then, you’ll need to wait for 2 hours before you test the chlorine levels to ensure they are safe. Waiting for 24 hours is ideal.

So, you may want to apply it after you have finished using the hot tub.

Liquid shock (sodium hypochlorite) leaves no residue and does not add calcium or cyanuric to the water. But it has a high pH level.

Still a tad unsure if shock and chlorine are the same?

In a recent article I published, I explored what is a hot tub sanitizer and if you could add sanitizer and shock at the same time. But I also explained how much chlorine you need to shock your hot tub.

Just click the link to read it on my site.

Why do hot tubs need to be shocked?<

Hot tubs need to be shocked, or super-chlorinated, to keep the spa water crystal clear and bacteria-free. Over time, organic materials like sweat, oils, and lotions build up in the hot tub water. These contaminants react with the sanitizing chemicals, reducing their effectiveness and causing the water to become murky and smelly. Shocking the hot tub helps break down these organic materials and reactivate the sanitizer, ensuring the hot tub remains a safe and clean environment.

Furthermore, hot tubs are a breeding ground for bacteria due to the warm, wet environment. The elevated temperature accelerates the growth of bacteria and algae, and if left unchecked, can cause issues like hot tub folliculitis, a skin infection. Shock treatments can kill these harmful bacteria, keeping the hot tub healthy for use.

Shock treatments also eliminate chloramines, a byproduct of chlorine and contaminants. Chloramines are responsible for the harsh chlorine smell often associated with pools and hot tubs and can irritate the eyes and skin. Shocking the hot tub removes chloramines, enhancing the overall hot tub experience.

Finally, regularly shocking your hot tub can extend its lifespan. It prevents scaling and staining of the tub’s surfaces and equipment, reducing maintenance costs in the long run. In essence, shocking is a crucial step in maintaining a clean, safe, and enjoyable hot tub.

What kind of hot tub shock is best?

Choosing the best type of hot tub shock depends on your specific needs and preferences. Two of the most popular types are chlorine shock and non-chlorine shock, each with its own benefits and drawbacks.

Chlorine shock, the more traditional option, is highly effective in killing bacteria, algae, and other contaminants. It’s known for its robust sanitizing capabilities, ensuring your hot tub is squeaky clean.

It’s also often more affordable than non-chlorine options. However, it has its downsides too. The strong smell of chlorine can be overpowering for some people, and it can cause skin and eye irritation in sensitive individuals. Additionally, it can cause wear and tear on your hot tub components over time, leading to potential maintenance issues down the road.

Non-chlorine shock, or MPS (monopersulfate) shock, is a chlorine-free alternative. Sometimes it is labeled potassium peroxymonosulfate.

It’s gentler on the skin and eyes, making it a great choice for people with sensitivities. It’s also virtually odorless, which many find more pleasant. Non-chlorine shock works effectively to oxidize organic contaminants in the water, but it does not kill bacteria the way chlorine-based shock does. It’s also typically more expensive than chlorine shock.

Ultimately, the best hot tub shock is the one that aligns with your personal preferences, budget, and specific hot tub needs.

How do you shock a hot tub?

Shocking your hot tub is a crucial step in maintaining its cleanliness and your safety. Regardless of whether you’re using chlorine or non-chlorine shock, the steps remain pretty similar. Here’s a basic outline:

1. Test the Water: Before shocking, test the pH and alkalinity levels to ensure they are within the recommended ranges. Chlorine works best with pH levels between 7.2 and 7.6, and alkalinity between 80 and 120 ppm.

2. Pre-Dissolve the Shock: Rather than just dumping the shock directly into your hot tub, it’s a good idea to pre-dissolve it in a bucket of water. This helps to distribute it evenly and avoids undissolved granules that could bleach your hot tub cover or pillows.

3. Add the Shock to the Water: Pour the dissolved shock into the water, ensuring to distribute it around the hot tub, not just in one area.

4. Run the Jets: Once the shock is added, run the jets for about 15-20 minutes to circulate the shock throughout the hot tub.

5. Cover and Wait: Finally, cover your hot tub and wait. Chlorine shock requires about 24 hours before the hot tub can be used again to allow the chlorine to drop to safe levels, while non-chlorine shock only needs about 15 minutes.

The choice between chlorine and non-chlorine shock depends on your preference. Chlorine shock is more potent and cheaper, but it can leave a strong smell and cause skin or eye irritation. Non-chlorine shock is less harsh, and doesn’t raise chlorine levels, but it’s generally more expensive and requires a separate sanitizer afterward.

How long after you add chlorine shock to your hot tub can you test the water?

Determining when to test your hot tub water after shocking it can depend on whether you’re using chlorine or non-chlorine shock.

If you’re using chlorine shock, you’ll want to wait a little longer before testing. Generally, it’s best to wait about 24 hours after you’ve shocked your tub to get an accurate reading. This gives the chlorine shock ample time to work its way through the water, killing off bacteria and breaking down waste. It’s worth noting that with chlorine shock, you may see a temporary spike in your chlorine levels immediately after shocking, which is normal.

Non-chlorine shock, on the other hand, doesn’t raise chlorine levels, so you can typically test the water sooner. Usually, waiting about 15 minutes after adding the shock should suffice.

While chlorine shock effectively kills bacteria and is usually less expensive, it can cause a strong chemical smell and might irritate your skin or eyes. Non-chlorine shock doesn’t have these downsides, but it requires the addition of a separate sanitizer afterward and is typically pricier. Regardless of the type of shock you use, regular testing is crucial to maintaining a clean, safe, and enjoyable hot tub. 

Conclusion

In conclusion, shocking your hot tub on a regular basis is a critical part of maintaining proper water chemistry. The process doesn’t just keep your hot tub clean, but also extends the lifespan of your spa cover and equipment by preventing build-up of harmful bacteria and mineral deposits.

The amount of time you should wait after shocking your hot tub varies, depending on the type of shock you use. Chlorine shock generally requires a longer waiting time, often up to 24 hours, while non-chlorine shock allows you to use your hot tub after just 15 minutes. It’s crucial to give the shock enough time to work its magic and fully sanitize your hot tub before diving in.

In all cases, patience is the key to best results. Rushing into your hot tub too soon could lead to skin irritation or an unpleasant smell. Always test the water after the suggested waiting time to make sure it’s safe and comfortable. The wait might seem long, but a perfectly balanced and sanitized hot tub is certainly worth it.

Ready to Spend Less Time On Maintenance and More Time Enjoying Your Hot Tub?

Let’s face it. Balancing the water, cleaning filters, dealing with rashes, and trying to figure out which chemicals to buy and add can make you feel more like a chemist than someone who just wants to relax after a long hard day!

That’s exactly why The Hot Tub Handbook and Video Course is so valuable!

This is from Matt over at Swim University and he developed it for people looking to save money, time, and frustration. His tips on chemicals can save you $100/year just by making sure you buy only what you need.

So if you’re ready to stop being confused or frustrated with your hot tub and start spending more time in it, check out The Hot Tub Handbook and Video Course.

Just click that link to learn more on their website.

Frequently Asked Questions

How long do you have to leave the cover off after shocking a hot tub?

After shocking your hot tub, it’s generally recommended to leave the cover off for about 15-20 minutes.

This is to allow any built-up gas or chemical fumes to dissipate into the air. If these fumes are trapped under the cover, they can potentially damage the hot tub’s cover and its internal system. Plus, it helps to prevent the accumulation of strong chemical smells. So, after you’ve added your shock, step back and let it breathe. Just remember, it’s still not the time to hop in quite yet.

Always wait until the recommended time based on your shock type, and don’t forget to test the water to ensure it’s safe and balanced before you take the plunge.

How do you know if you over-shock your hot tub?

Overshocking your hot tub can lead to a few tell-tale signs.

If the water becomes extremely cloudy or foamy, that could indicate too much shock has been added. Another sign is a very strong chlorine smell. While a slight chlorine odor is normal, an overpowering smell often means over-shocking. You may also experience skin, eye, or lung irritation when using the hot tub. Prolonged over-shocking can even cause damage to the hot tub’s components, including the pump, filter, and liner. Regular water testing is the best way to avoid this.

If you find your chlorine levels are too high, refrain from using the hot tub, keep the cover off, and let the sun and air naturally dissipate the excess chlorine.

How often should you shock a hot tub?

As a general rule, you should shock it once a week under normal use conditions.

This keeps the water quality high by breaking down organic contaminants and maintaining an optimal sanitizer level. However, heavy use or a large number of bathers can increase the demand for hot tub chemicals, and you may need to shock more frequently. In these scenarios, consider shocking after each use.

Additionally, if your circulation pump runs less often due to infrequent use or energy-saving settings, you might need to shock your tub more often to make up for the reduced filtration time. Always test your water before and after shocking to ensure the best results.

Should I shock my hot tub after refilling?

Actually, shocking your hot tub right after refilling may not be necessary, especially if the water used is fresh from a clean, treated source. The primary purpose of shocking is to remove organic contaminants and reactivate the sanitizer, which wouldn’t be relevant for brand-new water. In this case, adding a sanitizer immediately should be sufficient to maintain a clean and safe hot tub.

However, the one exception is if you’ve filled your tub with well water. This source can sometimes contain organic matter and other potential contaminants, so a shock treatment could be beneficial in this case. Remember, though, the key is consistent water testing and adjusting your maintenance routine accordingly to ensure optimal hot tub health.

Image that requires attribution:

Hot Tub by Michael (a.k.a. moik) McCullough is licensed under CC2.0 and was cropped, edited, and had a graphic and text overlay added.

Image by OpenClipart-Vectors from Pixabay

Jeff Campbell
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