Chemical treatment is a vital part of owning a hot tub or swim spa. Using the correct chemicals – and knowing how to use them properly – ensures your water stays clean, safe, and enjoyable all year round. Chlorine is the most commonly used sanitiser, but there are also effective alternatives such as bromine, along with additional water care measures that help maintain perfect spa conditions.
Before adding any sanitiser to your hot tub or swim spa (chlorine, bromine, etc.), it’s essential to balance the pH and alkalinity levels first. Using spa test strips makes this quick and simple. These strips typically measure free chlorine, pH, and alkalinity, clearly showing an “OK” zone for safe levels. While all readings are important, your main focus should always be on getting pH and alkalinity balanced first, as this allows sanitisers to work effectively.
Start by testing your water to check that pH and alkalinity are within the recommended range. Once balanced, you can add a shock dose of your chosen sanitiser – either chlorine or bromine. Shock treatment helps destroy any bacteria that may have developed in freshly filled water. This dose should be around 10% stronger than your regular top-up amount. Allow the shock to fully dissolve and circulate for 1–2 hours, then retest your water using test strips. Make sure your chlorine or bromine levels fall within the safe “OK” zone before using your spa.
If your chlorine or bromine level is too high, simply run your spa pumps and fold back the cover. This allows the sanitiser to naturally burn off. If your readings are too low, follow the manufacturer’s recommended dosage to bring levels back up safely.
Regular water testing and chemical maintenance are essential parts of responsible hot tub ownership. Without proper care, your spa water can quickly become unsanitary and may allow harmful bacteria, such as legionella, to develop. For personal advice and recommendations, speak to your hot tub dealer – they’ll be happy to help you keep your water crystal clear.