Jacuzzi Hot Tub Chemicals Guide

When it comes to owning a Hot Tub or Jacuzzi it is important to understand how different chemicals can affect the water. With that in mind, we’ve created this guide to explain how to get the most from your Hot Tub and Jacuzzi chemicals.

Important Hot Tub chemical definitions

Before we delve into the ins and outs of Hot Tub chemicals there are some specific Hot Tub chemical terms that are essential to understand.


Jacuzzi Chlorine Granules

A sanitiser is a disinfectant chemical used to kill bacteria that evolves within Hot Tub water, keeping the water safe for Hot Tub bathers. There are two popular sanitisers used to protect the water within Hot Tubs, these are Chlorine (the stronger of the two) and Bromine. If you’re a Hot Tub owner with sensitive skin, then the use of Bromine is recommended.


The term pH is a scientific way of describing whether your Hot Tub water is acidic or alkaline. The pH scale works from 0-14 with 7 being neutral, anything below 7 is classed as acidic while anything above 7 is considered an alkaline.

The ideal pH for Hot Tub water is between 7.2 - 7.4. A large variation outside this range either way can have detrimental effects.

PPM (Parts Per Million)

The amount of a particular chemical used in a Hot Tub is usually measured in ppm (parts per million) or mg/l (milligrams per litre). In Spas it is essential to keep the amount of Chlorine at between 2-3ppm.


Alkalinity refers to the amount of alkaline salt affecting the balance of your Hot Tub water. The alkalinity of your Jacuzzi’s water will also affect the water hardness. It is important to balance this accurately to help avoiding scaling.

Basic Hot Tub chemistry

Your Jacuzzi Hot Tub water must be chemically managed in order to keep it safer for bathers. The measured application of water balance chemicals will keep your Hot Tub water clean and free from mould growth and harmful bacteria for longer.

As Hot Tub water is warm, its chemical balance is constantly changing. That is why Hot Tub owners must ensure they monitor for any changes in the chemical balance of the water and act appropriately.

This guide has been designed to provide useful hints and tips on how to manage Hot Tub water easily.

What affects Hot Tub water balance

There are many different things which can affect the balance of the water in a Hot Tub or Spa. Being aware of these factors will allow you to stay on top of the cleanliness of your Hot Tub. Below are some of the most common reasons for a change in the water balance in a Jacuzzi:

  • The number of people using the Hot Tub changes
  • Heat/Temperature changes
  • Sunlight
  • The amount of water in the Spa
  • How often your Spa is used
  • The efficiency of Hot Tub filters
  • Body creams
  • Hard or soft water areas

With the above in mind it is important to understand the specific procedures that need to be undertaken to keep your Hot Tub water in a healthy condition.

Jacuzzi Hot Tub water procedures

Shock dosing

Jacuzzi Direct Non-Chlorine Shock

Shock dosing is the procedure carried out when you need to instantly deal with water problems in your Hot Tub by raising the levels of sanitisation. To adjust your water levels, Jacuzzi Direct recommends a dose of Chlorine or Non Chlorine shock.

Chlorine is recommended as it can not only act as a sanitiser but as a shock dosing too. Alternatively, a Bromine sanitiser can be added to your Hot Tub water. If this is the procedure you’re going to undertake it is advised to add a dose of Non Chlorine Shock also.

Calcium hardness

Calcium hardness refers to the levels of calcium salts which are affecting the balance of water in your Tub. Hardness is how we determine how corrosive or scaling the Hot Tub water is. When the water in your Hot Tub hits a state of “total hardness” you will notice scale within your Hot Tub and cloudy water.

It is important to keep some level of hardness though, as not enough calcium will force the water to draw from other minerals such as aluminium, copper and iron (particular parts of your Hot Tub are built from these materials).

You should ensure your Hot Tubs calcium reading is between 100 – 250PPM. If the levels of calcium hardness in your water are below this, Jacuzzi advises using Jacuzzi No Scale which is designed to keep calcium levels at the recommended level.


Flocculent is a chemical which is added to Hot Tub water to prevent it going cloudy over time. This chemical works by forcing smaller dirt particles to clump together until they’re large enough to be caught by the Hot Tub filter system.


Ozone is a gas based on active oxygen that will naturally kill bacteria and help disinfect the water within your Spa. You can create and release the gas to start this particular Hot Tub chemical procedure using an ozonator.

Hot Tub chemical safety

It is extremely important to stay on top of the water maintenance of your Hot Tub in order to keep the right water balance safe for bathers.

While Hot Tubs are treated in the same way as swimming pools there are some challenges involved with maintaining the quality of a smaller volume of water. Because of this, it is crucial that the person/s responsible for the quality control of Hot Tub water understands the chemicals they’re using.

Below are some important tips when using Hot Tub chemicals:

  • Always read the label of any Hot Tub chemical before use and follow the instructions carefully
  • Never mix Hot Tub chemicals unless instructed to do so by a Hot Tub specialist
  • Always pre dissolve any Hot Tub granules in a jug or container before adding them into your Hot Tub water
  • Always add chemicals to water, never the other way round
  • Never add chemicals to your Hot Tub water while it is in use
  • Only use Hot Tub chemicals in well ventilated areas
  • Beware of strong winds when using powdered chemicals
  • Keep all Hot Tub chemicals out of reach of children and animals at all times
  • Make sure you wash your hands after using Hot Tub chemicals
  • Jacuzzi Direct strongly advises wearing protective clothing whenever handling chemicals
  • Test your Hot Tub water on a daily basis (we recommend either Bromine or Chlorine test strips depending on your preferred sanitisation method)
  • Store Hot Tub chemicals away from heat and moisture
  • Always leave your Hot Tub switched on (unless changing Hot Tub filters or changing the water in your Hot Tub)

For more Hot Tub and Jacuzzi guides, check out our Hot Tub Inspiration & Advice Centre today.