Hot tub spas have the potential to become host to a plague of algae, other bacteria, unwanted impurities and organic matter. Chlorine is used to sanitise the water, helping to keep it clean and safe for bathers. During this process, chlorine levels can be broken down by sunlight, combine with impurities and deteriorate, reducing the 'free' chlorine level that is actively available to continue to sanitise the water. This is where hot tub shock treatments come in.

Hot Tub shock is also sometimes a useful fix for dealing with cloudy water. Applying chlorine shock should become a part of your regular routine.

WARNING: Chlorine levels after a shock dosing (sometimes called 'super-chlorination') are extremely high and as such bathing should not be allowed until the chlorine has returned to safe levels, as indicated on your test strips. After any dosing of any chemicals, please always test prior to bathing.