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What Chemicals Should Put I in My Hot Tub?

Keeping your tub in pristine condition will require the right mix of chemicals. So, what chemicals should you put in your hot tub? Find out here.

4 min read

Installing one of our NZ hot tubs is a wonderful way to relax and unwind, providing a soothing oasis in your backyard. But keeping your tub in pristine condition will require some basic chemistry. Start building your perfect relaxation retreat at home today, and discover the answer to the question: what chemicals should I put in my hot tub? 

Understanding Hot Tub Water Chemistry

Before you can understand what chemicals you should put in your hot tub, think back to your high school chemistry class. The water in your hot tub is a delicate ecosystem that requires careful attention and an understanding of the basics of water chemistry.

Basic Chemical Parameters

pH Level: The pH level measures how acidic or alkaline the water is.

Total Alkalinity: Total alkalinity helps stabilise the pH and prevent rapid fluctuations.

Sanitiser Level: Sanitiser levels are essential for killing bacteria and other microorganisms that can thrive in warm water environments.

Water Testing

Regular water testing is vital to monitor these chemical parameters accurately. You can use test strips or liquid test kits to measure pH, alkalinity, and sanitiser levels. Keeping track of these values can help you make informed adjustments to maintain the best water balance.

Water Balancing

Water balancing is the process of adjusting the pH, total alkalinity, and calcium hardness levels to ensure they are within the recommended range. If these levels are not correctly adjusted, it can cause discomfort, corrosion, and damage to the equipment.

Spa Pool Chemicals

The list of chemicals you should put in your hot tub is long, but it doesn't have to be scary! Discover the chemicals you'll need to brew the perfect spa pool experience.


Chlorine is the most common and widely used hot tub sanitiser. It effectively kills bacteria, viruses, and other contaminants in the water, ensuring a hygienic environment for you to enjoy. Chlorine is available in various forms, including granules, tablets, and liquids.

To maintain proper chlorine levels in your hot tub, regularly test the water and add the appropriate amount based on the test results. The ideal chlorine level typically falls between 1-3 parts per million(ppm), but you should always follow the manufacturer's recommendations for your hot tub.


Bromine is an alternative sanitiser to chlorine, offering similar disinfecting properties. It works well in hot water environments and is known for being more stable than chlorine, particularly at higher temperatures. Bromine is available in tablet or granule form.

Bromine is less likely to cause skin and eye irritation or produce a strong odour than chlorine. It is an excellent choice for individuals with chlorine sensitivities. However, bromine can be more expensive than chlorine and may require an additional oxidiser to maintain its effectiveness.

Other Sanitisers

Apart from chlorine and bromine, alternative sanitisers are available for hot tubs. Some popular options include saltwater systems, mineral sanitisers, and ozone generators. Saltwater systems use a salt cell to generate chlorine from salt, providing a more natural and automatic sanitising process. Mineral sanitisers utilise minerals such as silver and copper to help control bacteria growth, reducing the reliance on traditional sanitisers. Ozone generators produce ozone gas, which acts as a powerful oxidiser and sanitiser when injected into the hot tub water.

Ultimately, the choice of which sanitiser to use in your hot tub depends on your preferences, budget, and any specific sensitivities or requirements.

Hot Tub Chemical Application and Maintenance

Chemical Dosage

Proper chemical dosage is crucial for maintaining a clean and balanced hot tub. To accurately determine the appropriate amount of chemicals to use, follow the instructions provided by the manufacturer and consider the exact volume of your hot tub.

Chemical Schedule

A regular chemical maintenance schedule is key to keeping your hot tub water pristine. Carry out daily, weekly, and monthly tasks to maintain the chemical balance. Daily tasks may include checking and adjusting sanitiser levels, while weekly tasks might involve testing and balancing pH and alkalinity. Additionally, monthly tasks might include cleaning the filter and shock-treating the water.

Find the Perfect Chemical Balance with Spa Family

Finding the right chemical balance for your hot tub is vital to creating that perfect soothing experience. By following our guide, you will know what chemicals you should put in your hot tub and be able to master the art of hot tub chemistry.

For all your hot tub chemicals and spa pool parts, contact Spa Family today or browse our selection online.

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