Hot Tub Sanitisers

This post is one of a series of posts designed to help you maintain your hot tub water and ensure you have consistently crystal clear, clean hot tub water.

A sanitiser is a chemical added to your hot tub water that kills bacteria.

There are several different hot tub sanitisers but the two main types used by the majority of people are; chlorine and bromine. There is also non-chlorine and bromine alternative called Active Oxygen. All these sanitisers come in both a granulated and tablet form.

NB Chlorine Tablets are usually a different formulation (Trichlor) to Chlorine Granules (Dichlor) and are not recommended for use in a hot tub. Some hot tub manufacturers including Sundance Spas will invalidate your hot tub warranty if you use them. If you are unsure, seek advice and check your Hot Tub Owner’s Manual and warranty documentation.

Your hot tub holds a volume of water heated to around 35oC. It will have a filtration system to circulate and filter the water and it may have a UV Water Purification System. All Sundance Spas models are now fitted with the Clearray Active Oxygen System. Despite how good your filtration system is you will still need to add some form of chemical sanitiser to make sure that you don’t get bacterial growth in the water.

Bacteria can be naturally occurring in fresh water, they could be in your hose pipe or they could be introduced by you from your skin.

Once the bacteria are in the water and the hot tub water is heated, your hot tub can be the perfect breeding ground for bacteria.  The water is the perfect temperature for bacteria to grow and we as humans provide the food by taking in dirt on our bodies, shedding skin etc.

You need to test the water, ideally daily, to check that you have the required level of residual sanitiser in your hot tub water. To test you can use a test strip designed for testing hot tub water. There are a number of brands available, a couple of examples are AquaSparkle 4-Way Test Strips or Le Motte Insta 3-Way Test Strips. Both these brands test for both bromine and chlorine as well as pH and Total Alkalinity.

The required sanitiser levels are as follows:

• Free Chlorine – 1-3ppm
• Bromine – 2-6ppm
• Active Oxygen – 2.5-7.5ppm

The sanitiser is the most important thing for keeping bacteria at bay in your hot tub water. There are a few other things you need to keep a check on too to make sure your hot tub water is completely balanced. Check out our other blog posts to find out more:

• Maintaining Total Alkalinity and pH in Your Hot Tub Water
• Shock Dosing Your Hot Tub Water
• What To Do If your Hot Tub Water is Foamy or Cloudy