Owning a spa pool is a fantastic way to relax, but keeping the water safe and hygienic requires a reliable sanitiser. Chlorine is the most popular choice for hot tubs across New Zealand. It is highly effective at destroying bacteria and keeping your water pristine. However, using it correctly is key to avoiding cloudy water, skin irritation, or strong chemical odours.
Why Your Spa Needs Chlorine
Chlorine acts as both a sanitiser and an oxidiser. It actively kills harmful microorganisms that thrive in warm water while breaking down organic matter like body oils, cosmetics, and sweat. Maintaining the correct chlorine level ensures your spa remains a safe, inviting environment for your family and friends.
Step-by-Step Guide to Using Spa Chlorine
1. Test the water. Always start by testing your spa water using high-quality test strips. You are aiming for a free chlorine level between 2.0 and 3.0 parts per million (ppm).
2. Balance the pH first. Chlorine is significantly less effective if your water is too acidic or too alkaline. Ensure your pH level is sitting comfortably between 7.4 and 7.6 before adding any sanitiser.
-
Target pH: 7.2 – 7.6
-
Target Alkalinity: 80 – 120ppm
-
Target Calcium: Around 100ppm
Use a specialised water balance product to lock these levels in.
|
|
|
|
3. Measure your dose. Read the manufacturer instructions on your chlorine container carefully. The required amount will depend entirely on the water capacity in litres of your specific spa pool model.
4. Add the chlorine. Sprinkle the measured chlorine granules directly over the filter compartment area while the main pumps are running. This ensures the chemical is distributed evenly throughout the plumbing and the main tub.
 |
 |
5. Leave the cover open. Keep your hard spa cover fully open for at least 15 to 20 minutes after dosing. This allows the oxidisation gases to escape safely, preventing chemical damage and blistering to the underside of your cover.
 |
 |
 |
The Importance of Shock Dosing
Regular daily or pre-soak dosing keeps bacteria at bay, but a weekly shock dose is essential for long-term water clarity. Shocking involves adding a much higher concentration of chlorine to break down chloramines. Chloramines are the spent, inactive by-products of used chlorine. They are the actual cause of cloudy water and that strong, unpleasant chemical smell. A weekly shock resets your water and restores the sanitising power of your chlorine.
Looking for a Low-Chlorine Alternative?
If you have sensitive skin or simply dislike handling harsh chemicals, you can drastically reduce your chlorine usage. By incorporating natural enzyme treatments into your routine, such as the Biologica Spa Alchemy water balancer, the natural formula does the heavy lifting by breaking down organic matter. This means you only need a fraction of the standard chlorine dose to keep your water completely safe and clear.
Read more: Tired of Chlorine Smells? How to Switch Your Spa to a Chlorine-Free System