How Soon Can You Use A Hot Tub After Adding Chemicals?

By James Brockbank •  Updated: 05/30/21 •  16 min read

How soon can I use a hot tub after adding chemicals?

When adding chlorine, wait 30 minutes before testing the water again. For non-chlorine shock, wait 10 minutes. For chlorine shock, wait 20 minutes. Always test the levels before entering the hot tub. When you add chlorine or bromine to your hot tub water, wait a minimum of 12 hours before using it to allow the sanitizer to take proper effect.

Stop wasting time and money with hot tub maintenance and confusing water chemistry! The Hot Tub Handbook and Video Course will help keep your hot tub balanced, sanitized, and crystal clear all the time.

Check out my list of high-quality hot tub products to help keep your hot tub clean and running great all year long!

My recommended product to help you test your spa water for accurate pH, alkalinity, bromine, and chlorine readings is the AquaCheck Trutest Digital Reader.

Every week I find myself adding a small number of chemicals to my hot tub to make sure everything is okay.

However, I also want to use the spa after adding these chemicals but often need to wait a short while for the hot tub to mix the water properly.

If you’re a hot tub owner, it’s essential to maintain the chemicals in your water. Often, this means adding chlorine or bromine every few days and adjusting the levels of pH and alkalinity.

As a result of these chemical additions, many people wonder how soon they can use their hot tub again after adding these chemicals.

In this article, I will talk more about how soon you can use a hot tub after adding chemicals.

Let’s get started!

How Soon Can You Use A Hot Tub After Adding Chemicals

Chemicals in your hot tub water can be a delicate balance. So it’s crucial to maintain the levels of pH, Alkalinity, and Chlorine or Bromine, also known as sanitizers.

You should wait 12 hours before entering the hot tub when you’ve added either chlorine or bromine to allow it to take effect properly. When you first fill up your hot tub with fresh water, make sure some shock treatment is available to help shock the spa water from the beginning.

After adding chemicals like pH up and down and alkalinity reducer, you should wait about 1 – 2 hours before using the spa. If these types of adjustments for PH levels or alkalinity levels are made, then follow instructions that come with those products about how long they need to mix in your water before use.

If your hot tub smells like chemicals, check out our article on the subject for more information.

I also recommend these water test strips from JNW Direct Pool and Spa to test your water.

Consider Using a Water Care Monitor

Monitoring the health of your hot tub can often be challenging if you are not testing the water on a regular basis. This can also be a problem if you go on holiday or you are unable to take care of your hot tub due to mobility issues.

A test system I highly recommend is the Exact Industrial Test System. This system is great for hot tubs and pools and gives your a highly accurate digital readout of your water chemistry compared to other methods.

The pHin Smart Water Care Monitor for pools, hot tubs, and inflatable spas continuously tests the water and alerts you when to add chemicals with the integrated mobile app.

The mobile app will inform you when to add chemicals such as chlorine, and how much chemical is recommended. This is done by entering your hot tub or pool’s unique dimensions.

Simply scan the bar code of any chemical brand and the pHin app will calculate how much chemical is to be added to the water. Most products and brands are recognized by the application.

The pHin device will sample water more than 1000 times per week to give you an accurate reading compared to using test strips.

The pHin device works with different water types including chlorine, bromine, and saltwater hot tubs, swim spas, inflatable hot tubs, and pools.

This unique device comes with a lifetime warranty to ensure your water remains clear and ready for you to use at all times.

How Long To Wait After Adding Ph Up To A Hot Tub

After adding pH up to your hot tub, you should wait at least 2 hours before using your hot tub again. This is because you want the chemical to have time to work correctly and bring pH up for the water not to be overly acidic.

The recommended pH level for your hot tub water is 7. However, levels of between 7.2 and 7.8 can still be considered safe.

After a few hours, use one test strip to see if it is within range or not. If still too low, then add more pH up.

If you are unsure how much acid needs to be added after testing on just one test strip, then look online for what level will need a certain number of strips until green color appears near the middle part.

A low level of pH means that the water in the hot tub is quite acidic. This can only cause a lot of corrosion on the hot tub’s surface as well as on the equipment.

However, this can also make it uncomfortable for your family and the guests to enjoy the hot tub water. In addition, acidic water can irritate your eyes and remove natural oil from your skin. So, it will be left itchy and dry.

Things that can lower the level of pH in the spa are:

Our recommended product to raise pH in hot tubs is Spa Essentials pH increaser Granules.

How Long To Wait After Adding Ph Down To A Hot Tub?

You should wait at least 2 hours after adding pH Down to a hot tub before using it. Although you can only use this option if your water has a high pH and is more base, it will be okay for that period without lowering the pH level even further.

When the pH level of your hot tub is high, it means that it can leave scale on your plugs, filters, jets, pipes, etc. Water scale can decrease the flow and circulation of the water, too, resulting in increasing water pressure in the system responsible for proper circulation. This can put a lot of strain on the equipment of your hot tub.

Here are some of the primary reasons why the pH level of the hot tub can increase:

Using a pH decreaser such as sodium bisulfate can lower the pH level in your hot tub. Another way that you can use for reducing the pH level is by using Muriatic acid. You should use protective gear such as gloves for resisting chemicals and safety glasses while using this chemical as it is very acidic.

The process of lowering pH in a hot tub is advisable to be done on a hot day as this increases the effectiveness of the chemical.

But, if you want to lower your pH level while it is cold outside, you need an additional strategy in place. You can use sodium bisulfate because it will dissolve into the water at any temperature.

Lowering pH in a hot tub is essential because it will help maintain your hot tub’s sanitary condition.

Check out our full article on how to raise pH in your hot tub for more information.

Our recommendation to reducer your pH in your hot tub is to use pH Down from Hot Tub Things.

How Long To Wait After Adding Alkalinity To A Hot Tub

After adding alkalinity to a hot tub, you should wait at least 24 hours before using the hot tub. An alkalinity increase will help to maintain the pH level of your hot tub.

The varying level of alkalinity can harm the appearance of the water in the hot tub. This will give the water a slight green tinge. It can also result in a drying effect on your skin. A low level of alkalinity is quite severe and should be appropriately maintained. Low alkalinity can cause the water to appear green with rapid fluctuations in the pH level. This is because the water in the hot tub cannot respond to the effects of acid efficiently.

You can use chlorine or bromine as an alternative for alkalinity without waiting periods in between these actions and then finally use phosphate, which will increase the sanitary condition of your water.

If you are at a point where your hot tub is starting to have some problems, it may be time for you to add in alkalinity. The level of alkalinity will depend on what type of chemicals and water treatment has been used before.

Check out this great article from Frog Products about raising alkalinity in a hot tub.

To raise total alkalinity I recommend Spa Essentials Total Alkalinity Increaser.

How Long To Wait After Shocking A Hot Tub

After shocking your hot tub, you should wait 2 hours before you can use the hot tub again. This is because it takes time for the chlorine to disinfect water, and this process may take up to 12 hours, depending on how potent your shock treatment was.

Hot tub shock is the process of adding a hefty dose of oxidizer chemical to the hot tub water. This process is also known as oxidizing. An oxidizer is usually capable of breaking up organic compounds. Adding enough chlorine to this mix will kill any bacteria resulting in clean spa water. It’s important to shock your hot tub regularly for the best results.

You generate many organic contaminants into your hot tub every time you shock. The organic pollutants arise from lotion, shampoo, sunscreen, makeup, dead skin cells, hair, and any other remnants that your body acquires from the surroundings. The number of organic contaminants is more significant when many people soak in one hot tub.

Hot tub shock removes organic contaminants from your hot tub. Unfortunately, the shock also removes chlorine and other oxidizer chemicals that have been used to keep the water bacteria-free for a long time, so you need to add more of this chemical afterward.

The first few days after shocking is usually safe before adding any additional chemicals back into the mix.

You can reduce this problem by rinsing or showering before you soak into the hot tub. But not all the organic compounds are eliminated. That is why you must use the hot tub shock to break down the organic contaminants. This will help you avoid scum or cloudiness in the water after some time.

A hot tub should not stay shocked for more than 24 hours, and then you should shock again with a fresh dose of chlorine or bromine to ensure all those pesky little germs are gone! There are many different ways to keep your water looking clean, but shocking is by far one of the most effective methods.

Check out our full article in shocking your hot tub for more information.

The non-chlorine provides a good working environment for chlorine because it creates a “free chlorine” environment needed to kill bacteria. It’s also helpful when you use bromine because it activates and keeps the bromine more effective.

I recommended Leisure Time Non-Chlorine Shock.

Dichlor is a stabilized compound by cyanuric acid. This feature helps it to stand the spa’s heat. Experts recommend that it’s good to keep a close eye on your level of sanitizer. You should also shock your hot tub in the late evening if it’s located outside. Shocking it when the sun is shining increases the risk of losing away chlorine before sanitizing the hot tub water.

I recommended SpaGuard Enhanced Shock for dichlor chlorine shock.

How Long After Adding Chlorine Can You Test A Hot Tub?

You will need at least 2 hours before a chlorine test can produce any accurate results, but no less than 12 hours either. Testing for chlorine is essential to make sure your water is sanitized and safe for use.

Using proper test strips for a hot tub will make this job easier for you.

You can find these strips in most hardware stores or pool shops, and they are easy to use. All you need is a test strip, water sample (about an ounce), and pH testing liquid. Then, you dip the strip into your water sample, wait about 30 seconds then compare the result on the color scale with those of the included color chart provided by whichever brand you buy!

This will help ensure that your hot tub’s chemical levels are at safe limits and that all bacteria have been eliminated after sanitizing.

Check out our full article on chlorine tablets for more information.

Our recommended choice for hot tub chlorine tablets is the Rx Clear Chlorine Tablets found on Amazon. These tablets come in different-sized containers based on weight.

Our recommended choice for a hot tub chlorine tablet dispenser is this U.S. Pool Supply dispenser.

How Long After Adding Bromine Can You Test A Hot Tub?

I recommend testing the water for 2 hours after adding bromine. This will give your hot tub time to stabilize its chemical levels, which is necessary, so you have an accurate reading.

Testing bromine in your hot tub is an excellent way to check for any unwanted chemical reactions and make sure that the bromine levels align with what they should be.

While chlorine is used commonly for sanitizing swimming pools and water disinfection, bromine is often used for hot tub sanitation. Although a bromine sanitizer is more expensive than a chlorine one, it does offer some more benefits.

Bromine tablets are very effective at killing microbes and bacteria that would otherwise cause health problems. Every kind of solid contaminant on your skin gets dissolved in the tub water. Your hot tub filter won’t be able to catch these solids. But don’t worry, bromine is good at destroying them.

Check out our full article on bromine tablets for more information.

I recommend these Bromine Tablets from Spa Depot to add to your hot tub.

How Fast Does Chlorine Dissipate In A Hot Tub?

When a spa cover is off, UV rays from the sun will begin to deplete any chlorine that hasn’t been stabilized with cyanuric acids, such as lithium hypo. One ppm of unstabilized chlorine will dissipate in 15 minutes or less under direct sunshine. With a heated spa, this dissipation speed is much faster.

The amount of time it takes for chlorine to dissipate in a hot tub varies. It can take anywhere from six hours to one day to dissipate, depending on the concentration level and temperature entirely.

Chlorine evaporates more quickly at higher temperatures, so if you want your spa water sanitized faster, then heat the water a little bit before adding any chemicals. You should also keep an eye out for how long the chemical lasts and what kind of other side effects it may have, such as skin irritation or unpleasant odor.

The best time to add more chlorine is an hour before you enter the hot tub. That way, chlorine has time to work its magic and sanitize the water.
Some people even like to add a little more than usual so that they can enjoy their spa for longer without having to worry about when the following chemical change will need to happen.

Check out our full article on lowering chlorine in a hot tub for more information.

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When Should You Not Use A Hot Tub After Adding Chemicals?

Do not use a hot tub right after you add chemicals. You should wait at least 2 hours before using the hot tub again. The chemicals need time to work their magic and sanitize the water. Also, a higher concentration of chlorine is best because you’ll need to add chemicals less often.

There’s a particular order that needs to be followed when adding these products to ensure the water is being properly treated. Always read the instructions on the bottle for best results.

The perfect time is after about 24 hours have passed after adding chemical treatment and before entering back into the spa again.

How Soon Can You Use a Hot Tub After Adding Chemicals: Conclusion

How Soon Can You Use A Hot Tub After Adding Chemicals

In conclusion, it’s essential to follow the exact order when adding these chemicals. These are products that need time to work their magic and sanitize your hot tub, so you don’t want to add any other product in between them or before 2 hours have passed since the last chemical addition.

The best way to get hot tub water chemistry correct is to be patient. It’s not an easy process, but with the right products and a little patience, you’ll be able to enjoy your hot tub for years.

Check out this great article from Swim University about adding chemicals to hot tubs for more information.

I hope you found this article on how soon you can use a hot tub after adding chemicals.

If you’re having problems with green hot tub water, check out our full article on the subject.

Thanks for visiting

James Brockbank