In this guide, we are looking at Everything You Need To Know About Inflatable Hot Tub Chemicals.
It can be confusing – and maybe even a little scary – when you buy your inflatable hot tub, and realize you are going to have to buy some chemicals as well.
Well, please don’t worry. Our guide is here to explain all about the chemicals you need to buy and how to use them.
We also look at any issues you might have with the water in your hot tub, and have made an easy-to-read table which shows you what to do in order to solve those problems.
So even if you have zero understanding of chemicals, chemistry, or science, go ahead and read this article – and we suggest you refer to it from time to time – and you’ll be equipped to keep your inflatable hot tub functioning perfectly. We break it down for you, so you can understand all the different chemicals and the reason you put them in your hot tub water.
By working out what you need, we also hope we can save you money. After all, it’s too easy to buy up boxes of chemicals in those early days of confusion, only to find out that you didn’t really need them all!
We look at:
- Sanitizers – these keep your water clean and hygienic
- Oxidizer – also known as ‘shock’; it super-cleans the water and helps reactivate your sanitizer
- pH levels – checking that your water isn’t too alkaline or acidic
- Total Alkalinity – a.k.a TA, this enables you to control the pH of your water
- Calcium – stops the water from corroding your hot tub
First off, a sanitizer is the most important chemical you need to add to your hot tub water.
We have an article which goes into great detail about using sanitizers in your inflatable hot tub: How To Keep The Water Clean In Your Inflatable Hot Tub.
However, if you came here first, then a summary of the main points will definitely help you understand this crucial part of owning an inflatable hot tub.
The reason a sanitizer is the most important chemical, is because it keeps the water in your portable hot tub clean and hygienically safe. It does this by attacking and destroying any harmful bacteria and algae that might build up in the water. Hot water can be a breeding ground for all types of germs, so it’s vital you add a sanitizer to kill off these bacteria before they can do any harm.
Even if the water in your hot tub looks sparkling fresh and clean, you must add a sanitizer from the get-go so it can kill off any invisible nasties. In this area, never trust to luck.
So, from the moment you buy your inflatable hot tub, you need to have sanitizer ready to add before you set foot into the hot tub. Once the water is hot and bubbling away, that’s when you add your sanitizer – and from then on, you regularly check the level of sanitizer in the water is correct. If it is: fine. If it isn’t: you add some until it is at the correct level!
There are three different sanitizers to choose from, so you are going to have to decide which one you are going to use. There are advantages and disadvantages of each one; and generally it comes down to personal preference. The three sanitizers are:
Chlorine is the most popular inflatable hot tub water sanitizer by far. That’s because it’s very good at destroying bacteria, and it is the cheapest sanitizer you can buy.
However, it is also has a slight odor, and therefore some inflatable hot tub owners prefer bromine.
Do you remember going to the public swimming pool and there was that chemically smell everywhere? That was the smell of the chlorine that was added to the pool water. So if you decide to use chlorine in your inflatable hot tub, then that’s the smell you might get – although it will not smell anywhere near as strong, because your hot tub is a lot smaller.
Strangely, the smell of chlorine in a hot tub is actually a good thing. That’s because chlorine only smells like that when it is ‘dying’. And the reason it dies is when it attacks and destroys harmful bacteria in the water. So when you smell chlorine coming off the water in your portable hot tub, that means it’s doing its job!
There are two types of chlorine sanitizer you can choose from:
- chlorine granules
- chlorine tablets
To use chlorine granules as your sanitizer, you can either add the correct amount directly to the hot tub, and let the heat of the water dissolve them and the airjets send them swirling around. Alternatively – and the method we recommend – you put the correct amount of granules in a plastic pitcher, add some hot water from your hot tub, stir the water around until the granules dissolve, then pour the mixture into your hot tub. In this way, you know the granules have fully dissolved and set to work immediately.
Whichever method you choose, you still need to wait at least 2 hours before you can use your hot tub.
With granules, we always recommend buying them in a smaller-size container than you do with tablets. That’s because once the container is open, it’s more susceptible to moisture and decomposition than tablets. Our choice is for the 2lb bottle of SpaGuard Chlorinating Concentrate over on Amazon, which you can check out by clicking here.
2020 UPDATE: During the current Covid situation, it is often difficult to get hold of the small, 1-inch chlorine tablets which will fit the dispenser that comes with most inflatable hot tubs.
If your preference is tablets rather than granules, you can still buy the larger 3-inch tablets, but you’ll also need to get hold of a larger floating dispenser, such as the Milliard Chlorine Floater. You can see the current price on Amazon by clicking here.
You only need to put one 3-inch chlorine tablet into the plastic chemical floater, and drop the floater into the hot tub water.
The tablets are slow dissolving, so the chlorine will gradually spread through the water and start to work. Therefore, you will need to wait at least 2 hours before you get into the hot tub.
As the days go by, you regularly check the levels of chlorine in the water – which we explain in a moment – and add another tablet if required. On average, 3-inch chlorine tablets last a week. This means you are going to need a lot over the course of using your hot tub. Therefore, it’s worth saving money and getting hold of a super-large container of tablets, such as the 25lb tub of HTH Super Chlorinating tablets which are available over on Amazon.
Bromine is the second most-popular choice of sanitizer amongst inflatable hot tub owners. It’s equally effective as chlorine at keeping the water clean, and it has the advantage of being odorless.
However, bromine costs a little more than chlorine, and that prevents many people from using it. It also doesn’t last as long as chlorine, so you will need to add it more frequently to the water in your inflatable hot tub. This, of course, also drives up the cost.
As with chlorine, you can use either bromine tablets or bromine granules. The procedure for each is the same as with chlorine – the tablets fit into the plastic floater and dissolve through the water, the granules go directly into the water.
As with chlorine tablets, it’s always worth buying a large container of bromine tablets, as you’re going to use a lot over the course of owning and using your hot tub. One of the best options comes in a 4.5lb tub of SpaGuard Brominating Tablets. They’re also available over on Amazon, by following this link.
The main difference between chlorine and bromine, and one that you need to keep in mind, is that because bromine is slower to work in the water, you need to wait longer before you can get into the hot tub. The minimum recommended time is 4-8 hours, depending on the size of your hot tub.
TOP TIP: Some owners prefer to use a different method: they sprinkle some bromine granules into the hot tub at the end of the day, then slip the cover on and leave the hot tub to do all the work. The water is then ready-to-go by morning.
Again, we recommend you buy smaller containers of bromine granules, to avoid moisture getting in while you store them, such as SpaGuard Brominating Granules, which come in 2lb bottles over on Amazon.
Using minerals is a lesser-known option as an inflatable hot tub sanitizer. It’s most often a mix of silver, copper, and other minerals, which act together to kill the bacteria in the water.
However, minerals are not a substitute for chlorine or bromine! They simply reduce the amount of chlorine or bromine you need to add to your hot tub water. So if you want to use a mineral sanitizer, you are still going to have to add a small amount of either chlorine or bromine to work together with the minerals in sanitizing your hot tub water.
You’re also going to need some oxidizer as well. So as you can see, using minerals as your main sanitizer is not only a little more complicated, it can work out quite expensive as well.
That said, a number of hot tub owners much prefer using a mineral sanitizer, such as the SpaFrog Mineral Sanitizer, which fits into your hot tub’s filter. To check it our or to see what other hot tub owners are saying about this product, you can click here and head over to Amazon.
Checking the correct levels of sanitizer
Once you have added sanitizer to the water, and started using and enjoying your hot tub, you need to periodically check the sanitizer is at the correct level. It’s super-easy to do this, and requires no knowledge of science!
To do this, you need to get hold of some water-testing strips, such as the JNW Spa Test Strips, which are sold cheaply over on Amazon. You can click here to check out the latest offers.
You get 100 test strips in a small bottle, and each strip can be used to test 6 different chemical levels of the water in your hot tub. That’s because each strip has different patches on it: one tests the hardness of your water; another tests the pH of the water (more about that in a while); one tests the Total Alkalinity of the water (again, we cover that soon); and the next two test the chlorine and the bromine levels of the water. (The other patch shows you the Free Chlorine level of your water, but no need to worry about that, as it’s relevant for swimming pool owners.)
What’s really nice about the JNW Spa Test Strips is that there is also a free app, available on the Apple App Store and Google Play. This allows you to record your results, check the levels, shows the history of your hot tub water; it also has a downloadable E-Book of Instructions on the app, and you can email for help if you need it.
Sanitizer levels are measured in parts per million – or ppm – and you are checking that your sanitizer is at the correct level, within a very small range.
But rather than having to do some complicated math or reading off a complex scale, the test strip container has the scale in easy-to-read color coding. So you simply dip the test strip into your hot tub water, holding it about 6 inches under the surface for a few seconds. Then take the strip out of the water, wait about 20 seconds, and then hold the strip against the correct color scale.
As you can see in the photo of the bottle (above), there’s a handy rectangualr box around the correct color squares for each chemical level, so you can quickly see if your levels are in the correct range.
Inflatable Hot Tub Sanitizers
easy to use and control
aggressive bacteria killer
aggressive algae killer
good choice for anyone with sensitive skin
much less chemical content
needs shocking to reactivate
can irritate sensitive skin
pH levels need regular checking
|costs more to use
needs more frequent replacement
breaks down in sunlight
|still needs chlorine or bromine
needs shocking to reactivate the chlorine
clumsy to use correctly
(parts per million)
|1-3 ppm||2-4 ppm (tablets)
3-6 ppm (granules)
Your inflatable hot tub will need to be shocked every now and then. This is also known as oxidizing.
Basically, shocking your inflatable hot tub means adding large quantities of chemicals to the water to break down any organic waste there may be in the water, such as skin cells, hair, body oils, and so on. Shocking also destroys any contaminants that cause the water to smell or make the water turn cloudy or even green.
Shocking also reactivates the chlorine or bromine in the water – when it has been working hard and become a little ‘tired’ – turning it back into an effective sanitizer.
Manufacturers generally recommend shocking your inflatable hot tub every week, but it really depends on how often your use your spa and how many people regularly use it. We generally find that once every two weeks is fine, even with daily family use.
The amount of shock you need to add to your inflatable hot tub varies according to the product you are using and how much water your hot tub holds. You must always read the product instructions carefully to check the recommended amount required for your hot tub.
There are three types of shock you can use, depending on the sanitizer you use:
- chlorine granules – to be used if you use a chlorine sanitizer
- bromine granules – to be used if you use a bromine sanitizer
- non-chlorine shock – an alternative choice, whether you use chlorine or bromine sanitizer; also recommended for hot tubs with a mineral sanitizer
If you use a chlorine sanitizer, then chlorine granules are a highly effective way of shocking your hot tub, as they destroy any contaminants and matter in the water powerfully and quickly. They also oxidize the old dead chlorine, turning it into a gas, which then escapes into the air.
The drawback of adding chlorine granules as a shock is that it will give the water that strong chlorine ‘public swimming pool’ smell while it’s doing its work. Some people find this unpleasant as it irritates their eyes and nose. However, if you shock your hot tub overnight, then this reduces the effect. It doesn’t stop the smell happening, but it means you’re not around the hot tub while the shock is doing its work.
To shock your portable hot tub with chlorine granules, you should turn on the air jets, and add 1oz of granules for each 500 gallons of water your hot tub holds (that’s about 1 tablespoon of granules). Put the cover on and leave the air jets going for an hour, then switch them off, and leave your hot tub overnight (or for several hours if you’re doing it during the day time).
As we say, you don’t need to buy a special chlorine shock, you can use the same chlorine granules you use to sanitize your hot tub. If you use chlorine tablets, however, you are going to need to buy a container of chlorine granules. I’d get a 5lb tub of SpaGuard Chlorinating Concentrate. Amazon have a range of bundles to choose from, from a single bottle up to a 4 pack. You can read owners reviews of these granules or check out the current deals by clicking here.
If you use bromine as your sanitizer, than you can use bromine granules to shock your hot tub.
The procedure is the same as it is with a chlorine shock. The easiest way is to add a tablespoon of granules to your hot tub water at the end of the day, turn on the air jets for an hour and put the cover on, then turn the jets off at the end of the hour, and leave the hot tub overnight.
An advantage of using bromine as a shock means you don’t get the odor that you get with chlorine.
You can see that the bromine granules we recommend as a sanitizer are also great to use as a shock. These are the Spa Essentials Brominating Granules, which come in 2lb containers. If you follow the link, you can check out some great multi-pack deals over on Amazon, and also see what other hot tub owners say about this product.
An alternative to using either chlorine or bromine granules is to use a non-chlorine shock. This works in the same way as granules, to clean, refresh and re-boot your hot tub water. However, because it doesn’t contain chlorine, you don’t get that strong chlorine smell while it does its work.
To use non-chlorine shock, you follow the same procedure as you would for chlorine shock, by adding a tablespoon or two of the shock to your hot tub with the air jets turned on to circulate the shock through the water.
An advantage of non-chlorine shock, is that you don’t have to wait as long before you can use your hot tub, as there is no strong chlorine odor or high chlorine levels in the water. A great performing non-chlorine shock is GLB Oxy Brite which comes in a two-pack on Amazon.
Always Remember. . .
It’s important to remember that after you shock your hot tub, and before you get into the water, you need to use a test strip to make sure the chlorine or bromine level of the water is back at the correct level.
- If it is at the correct level, then you’re good to go.
- If the level is a little high, leave the cover off for a while and run your air jets. The excess chlorine or bromine will soon evaporate and you can use your hot tub.
- If the levels are a little low, add a small amount of the sanitizer granules you use to the water, or pop another tablet into the chemical floater. Then run the air jets and wait for 30 to 60 minutes before getting in.
pH and Alkalinity
In our article How To Test The Water In Your Inflatable Hot Tub, we look in great detail at how to check – and alter if necessary – the pH levels of your hot tub water.
As you’re here, though, we’ll distil that advice into a simple guide that will help you understand this area of inflatable hot tub ownership.
To start with, then, you need to maintain the correct pH levels of the water in your hot tub so that the sanitizer keeps working as efficiently as possible.
pH is a measure of how acid or alkali the water is in your inflatable hot tub. It uses a scale of 0 to 14 to show the pH value, with 0 being extremely acidic and 14 being extremely alkaline. The number 7, right in the center, is known as Neutral.
The pH value of the water in your inflatable hot tub should be between 7.2 and 7.8, which means it needs to be ever so slightly alkaline.
If the water is too acidic or too alkaline, then it can damage the water heater, filter, and massage jets. Therefore, you need to use a pH test strip, to make sure the water in your inflatable hot tub is at the right level.
We already mentioned that JNW Spa Test Strips are a good choice for testing the correct levels of sanitizer in your hot tub water. They also test the pH value of the water as well. (Other multi-test strips work just as well).
You’ll remember that the JNW Spa Test Strips have six separate patches on them – the bottom one shows the pH level of your hot tub water.
To check the pH level of the water, dip one of the strips into your hot tub water. Hold it about 6 inches under the surface for a few seconds, then take it out. Wait about 20 seconds, and then check the color of the patch against the pH scale on the test strip container. On the JNW Spa Test Strips, the patch needs an orange color for it to be ok.
You’ll see that this corresponds to a pH value of between 7.2 and 7.6.
If the pH level is too low or too high, you are going to have to adjust the level. Before you can do this, however, you need to check the Total Alkalinity of the water.
You don’t need to worry about going into great depth about the science of Total Alkalinity, other than to know how it affects the pH value of the water in your hot tub. Briefly, it’s a measure of how good the water is at resisting changes to the pH level which would make it acidic.
Basically, if the Total Alkalinity of water in your hot tub is too high, it will create a pH value that is also too high; this will make the water cloudy and create scale on the inner surfaces of the hot tub. If the Total Alkalinity is too low, then the pH value will be unstable and difficult to control.
Therefore, before you can adjust the pH of your hot tub water, you need to check the Total Alkalinity is right to start with. Otherwise, you won’t be able to get the pH level right and you’ll be wasting time, chemicals, and money!
So, to test the Total Alkalinity (TA) level, once again get hold of a test strip. Dip it into the water, again holding it about 6 inches under the surface for a few seconds. Then take it out and after around 20 seconds, check the TA reading against the color scale on the test strip container. With the JNW Spa Test Strips, this is the fifth patch on the strip, which you read off against the fifth scale down on the container. In our example on the right, you can see that the test strip patch has turned turquoise. If you look at the scale on the bottle, you’ll see this is within the acceptable range of between 120 and 180 parts per million (ppm).
If your hot tub water is within this range, you can go ahead and adjust the pH level as required. If the TA is outside of this range, though, you’re going to first need to alter the TA level before you can work on the pH level.
This probably seems really confusing: but don’t worry! Take a look at this table and you’ll see exactly what you need to do in each scenario:
|Problem||What you need to do||Best deal on Amazon|
|Add a pH increaser that does not affect the TA.||Check Out pH Increaser|
|Add a pH decreaser to lower the TA levels. Then add a pH increaser that doesn't affect the TA level.||Check Out pH Decreaser|
|Add a pH increaser to raise the level of both.||Check Out pH Increaser|
|Add a pH decreaser to bring the levels of both the pH and TA down.||Check Out pH Decreaser|
|Add a pH decreaser to lower the pH level to normal.||Check Out pH Decreaser|
|Add a pH decreaser to lower the pH level. Then add an alkaline increaser to raise the TA level.||Check Out pH Decreaser|
|Add a pH decreaser to lower the TA level.||Check Out pH Decreaser|
|Add an alkaline increaser to raise the TA level.||Check Out Alkaline Increaser|
The final chemical you need to consider is calcium. This is an important mineral to add to your inflatable hot tub water if you live in a soft water area. That’s because if the levels of calcium are too low, the water will corrode any working parts and shorten the life of your water heater and massage system. If you’re not sure if your water is soft or hard, there’s a useful map over on the USGS website you can check out by clicking on this link (opens in a new tab).
Alternatively, you can use a JNW Spa Test Strip to give you a reading. You’ll need to look at the first patch on the strip (see the photo). Any reading of 120 parts per million (ppm) and higher is fine. If your water has a lower reading than that, then your water is soft and you’ll need to add some calcium to your water.
If you do need to add calcium to your water, remember that you need to add it every time you fill your inflatable hot tub. If you click on this link to head over to Amazon and look at a product such as Spa Guard’s Calcium Hardness Increaser, you’ll see it’s inexpensive to buy. The great thing about calcium, is that once you have added it to the fresh water, you can forget about it until you drain your hot tub and then refill it with fresh water.
Inflatable hot tub troubleshooting
Despite your best efforts, there will be occasional times when your inflatable hot tub develops some problems and you need to deal with them. Our easy-to-follow table shows you the most likely problems and what to do. We truly hope it helps!
|The Problem||The Cause||What You Need To Do|
|Cloudy water||Filter problems||Replace the filter cartridge|
|Green water and/or
Slippery floor and sides
|Algae||Shock the water|
|Rough hot tub sides and floor||Too much calcium||Check sanitizer levels and adjust|
|Chlorine or bromine levels are too high||You have added too much sanitizer or shock||Run the air jets and allow time for the chlorine or bromine to dissipate|
|Chlorine or bromine levels are too low||You haven't added enough sanitizer||Add more sanitizer, and run air jets for 30 minutes before testing water again|
|pH readings keep changing||Alkalinity is too low||Raise the Total Alkalinity level|
|Sanitizer levels keep dropping||Excessive contamination or the hot tub has been left stagnant for too long||Shock (and shock again 24 hours later if required)|
|Foam on the water||Too much detergent in the water from peoples' bodies||Half-drain your hot tub and top up with fresh water; make sure your hot tub users shower well before getting into the tub in future|
|Test strips don't change color||Test strips are too old||Buy some more test strips|
As you can see, there’s a lot to get your head round when it comes to inflatable hot tub chemicals. But in all honesty, once you’ve owned your hot tub for a while, and carried out some level checks and adjustments on the chemicals, it’ll soon become second nature.
We also recommend you bookmark this article and refer to it when you are unsure what to do or simply want to refresh your knowledge.
For another useful guide, which is related to the area of water quality in your inflatable hot tub, you might want to check out our article When Should I Change The Water In My Inflatable Hot Tub? Thanks for reading!