The reason that sanitisers are used in spas is to ensure that the water is healthy by preventing and killing bacteria. This is achieved by continuously and consistently maintaining a level of sanitiser (disinfectant) in the water.
Chlorine is a commonly used chemical to achieve satisfactory bacteriological and chemical purity in spas. It must be present in the ‘free’ form to kill bacteria and oxidise organic matter derived from bathers. Provided the water is balanced, chlorine levels of between 3 and 5mg/l (ppm) are sufficient to maintain healthy, clean water. The free chlorine level can be tested quickly and easily using AquaSPArkle 4-Way Test Strips.