Investing in a hot tub can be a great way to relax, socialise, and experience hydrotherapy benefits, all from the comfort of your home. However, with owning a hot tub, comes the responsibility of cleaning it and keeping it in good condition.

An important part of this is making sure that your hot tub’s water is at the right pH level, and therefore safe to use. This guide will cover what you need to know when it comes to keeping your hot tub’s water in the best condition.

What is a pH level?

Before we get started on how you can measure and adjust your hot tub’s pH level, you might be wondering what that means.

The pH level is a measurement of how acidic or basic your hot tub’s water is. The pH scale goes from 0-14, with 7 being a neutral level – an example of a neutral-level substance is clean water. The closer you get to 0 on the pH scale, the more acidic a substance is, and the closer to 14, the more basic (sometimes known as an alkaline) a substance gets.

Source: BBC – The pH scale.

Why are pH levels important for hot tubs?

It’s important to keep your hot tub’s pH levels as neutral as possible to avoid making your hydrotherapy sessions unsafe and to protect your tub’s components. Try to keep your water between 7.2 and 7.4 on the scale for the best results.

Chemicals are needed to keep your hot tub’s water clean and safe from bacteria, which will start to slowly change your hot tub’s pH levels. Repeated use will affect your tub’s pH too, as natural oils from skin can change pH slowly over time.

To make sure your hot tub stays in the best condition it can, while also keeping everyone who uses it safe, it is recommended to test your water’s sanitiser, pH, and alkalinity levels regularly, and then make adjustments as necessary.

How to measure a hot tub’s pH level

Adjusting your hot tub’s pH level is much easier than it might initially seem. You can neutralise your water In a few easy steps:

  • Buy a pH probe or sensor to measure the pH levels in your water.
  • Identify whether your pH level is too high or low.
  • Add chemicals to increase or reduce the pH of your water accordingly.

How to make your hot tub a safe pH Level

You can balance your hot tub’s pH level by using pH adjusters to increase or decrease your water’s levels as needed. The aim is to get your hot tub’s pH to 7.2 – 7.4, which makes it both safe to enjoy, and beneficial to the lifespan of your hot tub’s components. Make sure your Total Alkalinity level is between 100 – 150 ppm when adjusting, which will help to stabilise the water’s pH level.

How to balance the pH levels in a hot tub

When it comes to balancing any of the levels in your hot tub or spa, it is important to remember to test the water thoroughly. Before making any changes, check the TA of your water. Getting a measurement of 100 – 150 ppm will ‘stabilise’ your water, making it much easier to balance your pH in future. Remember that adjusters and sanitisers change your TA too, so it’s important to check this level first.

When ready, use probes, sensors, or a testing strip to check the pH of your water. Then, add the correct amount of chemicals it tells you that you need.

Once any kind of adjuster is added, turn on the jets and let the water circulate for 10 minutes or so, giving the chemicals a chance to evenly disperse throughout the water. Then turn off the jets and test again. Repeat as many times as necessary.

When either increasing the pH in your spa or hot tub or decreasing it, read your pH adjuster’s instructions and only add the recommended dose at any one time. Remember to aim for a pH of 7.2 – 7.4 in your hot tub’s water.

You can find more information on what chemicals to use, and how often you should measure and adjust your hot tub’s level, in our hot tub chemical guide.

Having the wrong pH levels in your hot tub

What are the effects of hot tub water that’s too basic or acidic? These are the reasons you should aim for a neutral pH in your spa:

Low pH levels

The lower the pH level of your water, the more acidic it becomes, meaning your sanitisers will stop working as effectively as they should be. This can start to increase the risk of potentially harmful bacteria in your hot tub.

Acidic substances can also be corrosive, meaning your hot tub’s components can be damaged and worn away over time. Keeping a pH level of 7.2-7.4 ensures you get the longest lifespan out of your products and stops you from spending more on expensive replacements.

A lower pH level in your hot tub’s water may also cause irritation in your eyes or skin, so it’s important to keep a safe balance for your bathers too.

Low pH levels can be fixed by increasing the pH in your water to a safe, neutral level. There are many chemicals available to buy for combating acidic water in your hot tub.

High pH levels

On the opposite side of the scale, letting your hot tub’s pH level rise over 7.6 makes it become more ‘basic’, causing its own problems. Like with water that’s too acidic, high pH water can let harmful bacteria grow, making your spa dangerous to use.

High levels of alkaline substances can also cloud up your water, letting scale grow on the surface. This can make your bathing experience very uncomfortable, but more importantly, it can clog up important components like water filters.

High pH levels can be stopped by balancing your water to a neutral level using pH adjusters. If your tub’s water is too high about 7.6 on the pH scale, try adding more acidic chemicals to counteract these effects.

Total alkalinity

Another crucial thing to consider when balancing pH levels properly is Total Alkalinity (or ‘TA’ for short).

Although alkalinity is measured on the pH scale, your water’s total alkalinity is a different subject. The TA of hot tub water represents how hard it is to increase or decrease its pH, making balancing easier and less frequent.

We recommend keeping your spa’s TA between 100 – 150 ppm (parts per million). This level means your pH will not change too much, but chemicals like chlorine will still work effectively.

High alkalinity levels

Having too high of a total alkalinity level will make it incredibly hard to change your hot tub’s pH level, as there is a large ‘buffer’ that neutralises acid before it alters the water’s pH. A high TA will also make sanitiser chemicals like chlorine much less effective.

Low alkalinity levels

Having too low of a TA level makes your water much more susceptible to pH change, and can make it hard to balance it around the 7.2 – 7.4 pH level. This is because the pH changes much easier, so it can be easy to get stuck in a cycle of trying to raise and lower the pH level, commonly referred to as ‘pH bouncing’.

Learn more about hot tub ownership with Platinum Spas

Regular maintenance and servicing of your hot tub is the best way to not only keep it in good condition but also to keep your water safe for longer without constantly draining it and replacing it, and balancing your hot tub’s pH level is an important part of this maintenance process. So make sure to test regularly and thoroughly. It may seem intimidating at first, but once you get into the habit of regulating your tub’s pH, it’s a breeze.

Need a hand with your hydrotherapy? Platinum Spas has a wide range of hot tubs from all the best brands on offer. Get in touch with one of our experts for advice on picking and caring for the right tub for you, or read one of our other guides on cleaning and maintenance.

Jamie Smith
Latest posts by Jamie Smith (see all)

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