Hot Tub Chemicals Guide

What Chemicals You Need for a Hot Tub

Taking a soak in the hot tub is one of the best ways for you to wind down and relax. But, in order for your hot tub to last you as long as it possibly can, it is important that you maintain it. You also need to remember about hot tub chemistry.

Just like if you were to own a swimming pool, it’s important to make sure that the water in your hot tub is safe to get into and that the tub is as clean as possible. There are some spa chemicals that you absolutely need to have, which include sanitizers and shock treatments, and others that are optional but would definitely make the experience more worthwhile.

In this article, we will discuss whether or not you actually need to use chemicals for your hot tub, what some of the absolutely mandatory chemicals are, what other chemicals you can choose to use, as well as some suggestions for maintaining your hot tub as best as possible. Doing all of this will ensure that you will be able to use your hot tub for many years to come.

Are Hot Tub Chemicals Really Necessary?

cleaning for hot tub

We know that you might hear the word ‘chemicals’ and start to have second thoughts. But the fact of the matter is, you need to maintain your hot tub using chemicals, and that’s all there is to it.

Think about your bathtub, if you have one. You’re most likely not using any chemicals to maintain it, other than some cleaner that you will use to get rid of some of the grime every so often. But you don’t have to use anything other than that because, if you were to take a bath, you’d fill up the tub and drain it when you were finished.

But the same can’t be said for hot tubs. You will generally keep the same water in your hot tub for weeks or months, depending on how frequently you clean it. And we all know how much bacteria and other microorganisms love warm and moist environments, such as the one that hot tubs provide.

If you don’t use the proper chemicals to maintain your hot tub, the number of bacteria that will grow is definitely not going to be safe for your health, nor is that hot tub going to be something that you will want to soak in. Simply cleaning leaves and other debris out of your tub if it’s outside is not enough for maintaining it.

You need to use the right chemicals to make sure that everything is the way it’s supposed to be. Not only will failure to do so lead to you having a lot more work to do in the future, but it also could lead to your tub’s operation failing, and you could definitely get sick from the bacteria that has grown in the tub over time.

With that being said, there is a way to keep your hot tub clean without using chemicals, but it’s much more difficult and time-consuming. You would have to drain the tub and refill it every time you use it (which is a huge waste of water), and you also need to make sure that the same water is not kept in the tub for more than 12 hours at a time. This is definitely not something we’d recommend due to the amount of water waste and, again, no one has the time to go about draining and refilling a hot tub every single day.

So, in short, it’s best that you make sure to keep all of these chemicals on hand whenever you clean your hot tub.

Are these chemicals safe, though?

Of course, since using these chemicals is what will keep the water in your hot tub clean and maintained, it’s not wrong to assume that they are safe- in a sense. You’re going to have to use them regardless, but here are a few things to keep in mind to make sure that you stay safe when you need to clean your hot tub using chemicals.

  • Don’t get in the hot tub for 24 hours after you’ve added the chemicals to the water. This is to make sure that all the chemicals have completely dissipated and that the chlorine levels are where they need to be.
  • Make sure you read all the labels and follow the instructions carefully. Never use any chemical without knowing exactly how you’re supposed to use it.
  • Never mix your hot tub chemicals. As we know, sometimes mixing two chemicals can cause a bad reaction, which could lead to any number of dangerous consequences. So, unless a specialist specifically tells you to do so, never mix any of the chemicals together.
  • Keep the chemicals away from warm and moist areas. If your hot tub is inside, you ideally will not want to keep the chemicals near the hot tub. And with that being said…
  • Keep the chemicals away from children. This should be a no-brainer, but you never want children having access to any type of chemicals, whether they’re meant for the hot tub or not! Keep your hot tub chemicals far out of children’s reach.
  • Only use these chemicals if you’re in a highly ventilated area. You won’t have to worry about this if your hot tub is outside, but if it’s inside, make sure that the hot tub was initially installed somewhere that has a lot of ventilation, and keep the windows open when you’re working with the chemicals.
  • Add the chemicals to the water. Don’t lay down the chemicals first and then add water.
  • Wear protective clothing. Since you will have to be dealing with chemicals such as chlorine or bromine, you definitely want to avoid getting those on your skin or face. You also probably don’t want to be breathing these in too deeply. Make sure that you wear gloves, goggles, and other protective gear when working with these chemicals.
  • Don’t use powdered chemicals on windy days. If your hot tub is outside, you want to be careful about its maintenance if it’s a windy day.
  • Wash your hands when you’re finished. This is to make sure that you stay safe if you have had any potential exposure to the chemicals you were using.

At the end of the day, you were using chemicals, so there are some things you will need to do in order to stay safe while using these chemicals. However, to ease any worries about whether or not hot tub chemicals are going to be dangerous, you will be safe if you take all the necessary precautions.

And now, let’s get into some of the absolutely mandatory chemicals that you need to make sure you have on hand when you get a hot tub.

Must-Have Hot Tub Chemicals

There are certainly some chemicals that you will be able to choose between when you get a hot tub, but all the ones included in this part of the list are the ones that you need no matter what.


This may be the most important of the different chemicals because it is what will keep your hot tub clean and sanitary. If you particularly enjoy having lots of guests over, having some sort of sanitizer is what will keep your hot tub clean and what will prevent you from catching any of the bacteria, illnesses, or anything else that other people might carry.

There are several different sanitizers you can choose between.


Chlorine is, of course, the most popular option out of all the different sanitizers you can choose between. It’s cheaper, it’s easier to use and maintain, and you can be assured that all bacteria and algae will be killed off rather aggressively. It works the same way as bleach does when you want to do any work in your bathroom. Chlorine works rather quickly to make sure that all fungus, viruses, bacteria, and other potentially harmful substances are killed off in your hot tub’s water.

You will notice the chlorine smell, which is the result of a chemical reaction. When chlorine interacts with any of these substances, it kills off their chemical components. This process produces waste referred to as chloramines, which is what causes the chlorine smell. You will want to test the level of chlorine because you shouldn’t be able to smell it (if you can smell it, then it means the level is below what it needs to be). The proper level should be between 1 and 3 parts per million.


The next most popular option is bromine. It’s easier to keep the water levels in balance if you decide to use bromine due to the fact that it has a lower pH. Bromine will also last longer and be gentler on your skin. However, it does not work as quickly as chlorine does to get rid of all the contaminants and it will burn off if your hot tub is outside. It’s the best option, therefore, if you have an indoor hot tub.

In order to get rid of all the bacteria and other substances that are lingering in your hot tub’s water, bromine will ionize all of their components, which means that the molecular structure of bacteria, viruses, fungus, and anything else will be destroyed. This will end up producing bromamines, which do not have a smell and aren’t anything that you should worry about for your health. However, if these components add up in the tub, then it could impact how effective bromine is. This is why you want to make sure that the bromine levels are where they need to be. The level should be between 3 and 5 parts per million if you choose to use bromine in your hot tub.


This is a sanitizer that does not contain any chlorine, so it might be a good choice for you to consider. There are some issues with using this product, however. For one, it does tend to be more expensive than chlorine and bromine, so you are looking to spend more than you normally would. And it could cause some parts of your hot tub, such as the rubber and plastic, to wear away over time. This is why it’s important for you to check with the company that manufactured your hot tub before you choose to use biguanide.

However, there are some advantages that make this a popular option. It works just as effectively as chlorine and bromine do and it does not need to be used in your hot tub as often in order to be effective. You will not notice any odor if you choose to use this product, and, according to many people, the water tends to feel a lot smoother. In order for it to work properly in your hot tub, the level of biguanide should be between 30 and 50 parts per million.


Some people choose to get a saltwater hot tub, just like they prefer to have saltwater pools. In order to do this, you will need to get a salt-chlorine generator. These hot tubs do use chlorine in order to stay sanitized, but you don’t actually need to purchase chlorine for this to happen. This is where the work of the generator comes in. The generator will turn the salt into chlorine, so you will simply need to buy salt. And you will find that this is a lot more budget-friendly because salt is less expensive than chlorine.

You will also find that the water is a lot gentler and does not dry out your hair and skin as much as regular chlorine water does. You will need to purchase special test strips that are meant to be used in saltwater if you choose to use this. The proper levels for salt are anywhere between 2,000 and 3,000 parts per million, and the right chlorine level is just the same as in a regular chlorine hot tub- between 1 and 3 ppm.


You should use shock in your hot tub on a weekly basis in order to make sure that the sanitation levels are where they need to be. However, depending on how many people use your hot tub, you may need to use shock on a more frequent basis. So, the reason why this chemical is important is because it will keep your hot tub extra clean, especially when you’re using it more frequently. Shock will also work if you’ve noticed algae, cloudy water, or anything else that isn’t so normal for a hot tub.

If you have a chlorine hot tub: You can get a special chlorine shock, a non-chlorine shock, or you can choose to use more chlorine.

If you have a bromine hot tub: You can once again use special chlorine shock, a non-chlorine shock, or more bromine.

If you have a mineral hot tub: Mineral hot tubs do not operate using a lot of chlorine, so you should get a shock that does not have chlorine in it.

If you have a biguanide hot tub: If you use biguanide as your hot tub’s sanitizer, this substance comes with its own special shock depending on the brand that you have chosen. You will need to make sure that the pH and alkalinity of the water are balanced correctly in order for the shock to work properly.

Alkalinity and pH

In order for your hot tub’s chemistry to be balanced correctly, it is imperative that you check on the tub’s alkalinity and pH. First, you will need to work on the alkalinity, because this is what acts as a sort of ‘buffer’ for the pH. Make sure that you have an alkalinity increaser. You need to make sure that the levels are right because having low alkalinity will make your hot tub’s water acidic.

If you notice that the alkalinity is too high, you will need to use a pH decreaser. It is important to realize how much these two components depend on each other to operate efficiently. Some people find it a bit difficult to get these balanced properly, but in time, you will find that it’s not that difficult as long as you follow all the instructions carefully.

Your hot tub should have an alkalinity level between 125 and 150 parts per million. Once this level has been reached, you are free to move on to the pH level.

  • If you notice that the water in your hot tub is cloudy… This is usually a sign of high pH. If you notice that the pH level is too high, you will want to use a pH decreaser.

Have a pH increaser on hand, too. If you notice that the pH levels are too low, and you use the pH increaser, you will also have to check for the alkalinity levels again. Keep in mind that you’re going to want to have test strips on hand because you will have to measure the water levels multiple times in order to get this step just right. Don’t get too frustrated if this does not work out for you on the first try.

  • Understand: If the alkalinity and pH are too low, your hot tub can get damaged because of how acidic the water is. If they are too high, then scaling could occur, which will also damage the hot tub. The acid will cause the heater to deteriorate, whereas the high pH will cause scaling around the heater, which will make it a lot more difficult for your hot tub to heat up.

The proper pH level should be between 7.4 and 7.6.

Recap: You will need an alkalinity increaser, pH increaser, and pH decreaser. And, of course, make sure that you have plenty of test strips on hand.

Calcium Hardness

You will want to check for this anyways, but some people live in areas where there is hard water. Even though this causes problems in your bathroom, this is actually good for your hot tub. Having a higher level of calcium will make sure that soft calcium will not eat away at the hot tub and cause it to deteriorate.

If the level of calcium in your hot tub is too high, however, it can cause the other chemicals that you’ve used to not dissolve properly. It will also cause cloudy water and scaling. If you notice that this is the case, you will have to drain your hot tub and scrub it. In order to make sure that the calcium level in your hot tub is where it should be, get a calcium hardness increaser.

The level should be between 175 and 250 parts per million.

Chemicals You Should Have

All of the chemicals we listed above are mandatory no matter what kind of hot tub you choose to get. But the rest of the chemicals that will be included on this list are not necessarily mandatory depending on where you live, what kind of hot tub you have, and other such conditions. Double-check to see if these apply to you.

Hot Tub Enzymes

This is especially recommended if you have an outdoor hot tub. Enzymes will help to break down any of the substances that will get in your hot tub after being exposed to the outdoors, such as twigs, insects, leaves, and anything else. If you let these go in your hot tub for too long, then you will end up with hot tub scum. It’s not a mandatory chemical, though, especially if you have an indoor hot tub.

Water Clarifier

Water clarifiers should never be used in replacement of the other chemicals included on this list. However, getting this chemical could be helpful in a pinch. You might notice that the water in your hot tub is looking a little bit cloudy, for example, but you’re having guests over soon and don’t have time to give your hot tub a thorough clean. However, once again, make sure that you don’t use this as a substitute for actually cleaning your hot tub, and be sure to give your hot tub a proper clean when you’re done using the hot tub.


This is also not totally necessary for your hot tub, but getting defoamer could be an option if your hot tub tends to get a lot of foam. Hot tubs typically become foam if the water becomes contaminated with lotion, soap, cosmetics, and oils. Using a defoamer will not damage any of your hot tub’s equipment, nor will it cause the filters to clog. As soon as you pour the defoamer in the hot tub, the foam will go away.

Spa Cleaner

You can also choose to add a spa cleaner to your collection. The purpose of this product is to clean the spa shell, or the actual tub itself. You can also use a spa cleaner to polish the tub so that it looks extra shiny. There are many different ways in which you can choose to clean your hot tub, including household items, but some people find that using special spa detergent is a lot more effective for them.

Spa Fragrances

This isn’t necessarily a ‘chemical,’ but it is an option for if you want to add something special to your hot tub. You will be able to find many different fragrances to suit your tastes that you will be able to add the water in your hot tub to make sure that it is smelling good at all times.

Tips and Tricks for Using Hot Tub Chemicals

Now that you have a good idea about what chemicals you will need to have for your hot tub, you may be wondering some different things about how to use these chemicals and whether or not this is actually an easy process. While some factors, such as making sure that the alkalinity and pH are in balance with one another, might seem to be a nuisance, you actually will be surprised to find how easy it is to maintain your hot tub using these chemicals. So, here are some of the best tips to keep in mind for when you go to add chemicals to your hot tub.

  • Keep your hot tub’s cover open. This isn’t necessarily for safety reasons as much as it is for smell purposes. The gasses from these chemicals will be released into the air, so you want to make sure that the cover of the hot tub is open so that you won’t have to deal with the smell. You want to make sure that the chemicals dissipate, so providing a lot of ventilation is essential.
  • Make sure that the water is running. Keeping the jets on when you add the chemicals to the water will ensure that the chemicals mix in with the water thoroughly, which will thus cause them to work as they should.
  • Always have test strips on hand. You always need to have test strips with you to make sure that you know what the water levels are. Before you add any chemicals, you need to test the water to make sure that the levels are where they need to be or so that you can get a better picture of how much of a certain chemical you need to add. And when you add the chemical, you will need to pull out the test strips again to make sure that the levels are where they need to be. And, before you get into the hot tub later on, you will want to get a test strip to make sure that the chemicals have done their job. For some of these steps, you will need to use multiple test strips. So it’s always a good idea to have an abundance of them with your hot tub supplies.
  • Make sure that the air valves are off. Keeping the air valves on will cause the chemicals to be released into the air a lot faster than they should. You want to make sure that the chemicals mix in with the water thoroughly and for as long as they need to. Having the air valves off will keep the chemicals in the water for longer.
  • Make sure you read and follow all the instructions carefully. You never want to work with something like chemicals before you know what you’re doing. Some chemicals cannot be mixed with others and others might have special instructions for use. None of us like to read the directions, but this is important for your safety and to make sure that the chemical will do its job properly. The instructions will tell you how much of each chemical you will need to add to the water in order for them to work properly.
  • Measure everything before you pour it in the tub. You don’t want to just take the bottle and pour the substance into the tub. You want to make sure that everything is measured properly in accordance with the instructions. This is important so that the water levels will be even and where they need to be.

Keeping Your Hot Tub Clean

In the meantime, making sure that you follow these steps to make sure that your hot tub is clean will allow you to lose less of these chemicals less often. The more you do your part to make sure your hot tub is clean, the less likely it will be that you will need to balance the pH or any other factor.

  • Clean the filter. You will want to clean the filter rather frequently to decrease the amount of debris and other substances that are floating in your water.
  • Shower before you get in the hot tub. Some people might feel as though this will entirely defeat the purpose of using a hot tub, but it’s an important step if you want to make sure that your hot tub won’t get as dirty. You will remove all the oils and other dirt from your body, which will help to keep the hot tub cleaner.
  • Keep the hot tub covered. This is true whether you have an indoor hot tub or an outdoor one. An indoor one needs to be covered to prevent too much dust and other substances from getting inside, whereas closing an outdoor hot tub will prevent bugs, leaves, twigs, and more from contaminating the water.

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