If there’s one thing that hot tubs are known for, it’s their soothing and relaxing nature. After all, few things can really compare to sitting back in a warm, bubbling hot tub at the end of a long week and letting it dissipate all your stress.

Of course, this is only going to be the case if you take the time to look after your hot tub properly, which is why it’s essential to have a proper understanding of the importance of using and maintaining hot tub chemical levels in your spa bath.

In particular, this means taking the time to research more about the different hot tub sanitisers out there, such as bromine and chlorine, and then settling on which one of these water cleansing options is going to be best suited for use in your at-home spa system.

So, if you’re considering using chlorine in your hot tub rather than bromine, here’s what you need to know about how much chlorine to add to a hot tub first time, and how much chlorine to add to a hot tub daily.

What does hot tub chlorine do?

Before going into greater detail on exactly how much chlorine to add to a hot tub, it’s worth explaining why exactly it’s so important to have chlorine in a hot tub to begin with. Surely it’s possible to use your hot tub without chemicals?

Well, the reality is that, while certainly feasible to use a hot tub without any sanitiser, we would not recommend it. As the name implies, the purpose of a hot tub sanitiser like chlorine is to keep your water clean and safe for bathing.

Simply put, without sanitiser, your hot tub will quickly become a melting pot for the kind of water-bourne bacteria that could be harmful to your health, not to mention turning your tub’s water green with mould, mildew, and algae – making for a less than pleasant bathing experience.

How often should you add chlorine to a hot tub?

Generally speaking, there are no set guidelines for when you should add chlorine to your hot tub, and it’s typically left to the judgment of the hot tub owner. For example, some owners may only put fresh chlorine in their hot tub every week, while others may do so on a daily basis.

However, a good rule of thumb for adding new chlorine in your hot tub is to test its sanitiser levels every few days and add additional chlorine as and when required based on the instructions given by your chosen sanitiser product – that way you can be sure your hot tub will be safe to use, but you won’t have to check it every single day.

How much chlorine to add to a hot tub first time?

Unlike with regular hot tub sanitisation, where you may only have to add a dash of chlorine here and there to maintain cleanliness levels, when adding chlorine to your hot tub for the first time or after a refill, it’s always best to add a little bit more than you might think.

For example, most hot tub chemical experts suggest adding at least 3-5 grams of chlorine (or 3-5 parts per million) for every 100 gallons of water in your hot tub. However, if your chosen sanitiser specifies differently, then it’s always considered best practice to follow those instructions instead.

From here, however, you should aim to keep your hot tub chlorine levels below 5ppm to avoid the side effects associated when bathing in overly chlorinated water.

How much chlorine to add to a hot tub daily?

As we previously noted, how much chlorine you need to add to a hot tub on a daily basis will depend on the current chlorine level of your hot tub’s water. Naturally, there are a variety of factors that can affect how often you’ll need to re-sanitise your hot tub water, such as:

  • The level of chlorine present – regardless of the other factors impacting your water’s sanitisation levels, how much chlorine is currently present in your water will be the main dictating factor in how much chlorine to add to a hot tub daily.
  • When you last shocked your tub – hot tub shocking is the chlorine equivalent of power-washing your tub and involves using large doses of chlorine to rapidly sanitise your tub’s water. Therefore, if you’ve only recently shocked your tub, you likely won’t need to add fresh sanitiser to your water mix.
  • The type of chlorine used – while chlorine tablets tend to be the most common form of chlorine used for hot tub sanitisation, there are also liquid and granule alternatives as well. So, depending on which form of chlorine you use, you may have to add more or less during your daily sanitisation routine.
  • How often you use your hot tub – it naturally goes without saying that, the more you use your hot tub, the more often and the greater amount of new chlorine you will need to add between uses.
  • The size of your hot tub – the larger your hot tub, the more chlorine will be needed to keep its water fresh, meaning more chlorine will be needed on a daily basis to maintain proper sanitisation levels. The same is also true for different filtration systems, with more powerful filters needing less chlorine to be effective in their cleaning.

Regardless of the factors impacting your hot tub sanitiser levels however, you should only ever add the amount of chlorine specified by your chosen sanitiser in relation to your hot tub’s current chlorine levels, otherwise, you risk over-sanitising your tub.

How much chlorine to shock a tub?

As we previously noted, shocking a hot tub is a much more intense way of sanitising your hot tub than simply adding a gradual increase in chlorine to your tub’s water, with most experts suggesting a total of 35g of chlorine shock per 1,500 litres of water.

However, much like when adding standard chlorine sanitiser, it’s always best to stick to the instructions provided on your chosen chlorine shock product to ensure a satisfactory outcome and avoid potential mishaps.

What are the different types of hot tub chlorine?

Now that we’ve noted what levels of chlorine you might want to add to your hot tub depending on different scenarios, we felt it worth touching on the specific different types of hot tub chlorine sanitisers available so you can have a better understanding of how they work:

  • Chlorine tablets – slow dissolving tables, chlorine tablets are one of the more common types of chlorine sanitiser, typically being added to a hot tub via a floating dispenser or in-built chlorinator.
  • Chlorine granules – the opposite of chlorine tablets, chlorine granules dissolve rapidly in your hot tub water for fast sanitisation.
  • Liquid chlorine – another fast-acting sanitiser, liquid chlorine solutions are added straight to your hot tub for rapid impact.

Which type of sanitiser you use is up to you, and we recommend experimenting with all of them to find the type which best matches your personal sanitisation needs.

How many chlorine tablets are needed for a hot tub?

As we’ve noted many times throughout this blog, how much chlorine you need to add to your hot tub will depend on many factors. However, in general, when it comes to the number of chlorine tablets or granules you want to add to your water, you can use the following as a basic guideline:

  • Chlorine tablets – 1-2 tablets per 500 gallons.
  • Chlorine granules – 1-3 tablespoons per 500 gallons
  • Liquid chlorine – 1-3 ounces per 500 gallons

Choose your first hot tub with Platinum Spas

So, now you know exactly how much chlorine to add to a hot tub, depending on different factors and necessities. Again, when it comes to sanitising, always follow the instructions provided on your sanitiser to ensure you’re adding the right amount of new chlorine for the current chlorine levels in your tub.

Of course, in order to sanitise or balance the pH levels in a hot tub, you’ll first need to install one in your home. And for that, you need look no further than the Platinum Spa hot tub and swim spa collection.

Whether this is your first time investing in a hot tub, or you’re simply looking to replace your old one in the future, we have hot tubs to suit users of all hot tub owning experience in our range.

Get in touch today to learn more about what our hot tub models can offer you and then book an appointment in your nearest hot tub showroom to see your preferred tubs in person. Don’t forget to visit our hot tub owner’s hub as well for more hot tub maintenance guides like this one.

Jamie Smith
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