The bactericidal effect of chlorine decreases significantly at pH > 7.8, while bromine remains effective within the pH range of 8.0–8.5. This means that users do not need to frequently adjust the water quality in a spa hot tub.

Adding magnesium, such as magnesium sulfate (Epsom salt), to the water in a spa hot tub is only acceptable if the salt content does not exceed the recommended range. Especially when the total salinity exceeds 1500 ppm, it may cause corrosion or damage to the internal components of the hot tub.

1. Preparation • Check water temperature • Check pH level • Wear protective equipment 2. Flushing Operation Steps • Calculate dosage • Dissolve the flushing agent evenly • Start the circulation system • Check residual chlorine or bromine concentration 3. Post-Flush Water Treatment • Maintain circulation • Clean the filter • Check and adjust pH level

Hot Tub Folliculitis (or Hot Tub Dermatitis) is a skin infection syndrome caused by contact with a contaminated hot tub. It is usually caused by a bacterium called "Pseudomonas aeruginosa". When people soak in a poorly maintained or inadequately disinfected hot tub, the bacteria enter the hair follicles or the stratum corneum of the skin.

A spa hot tub consists of multiple systems, and not all systems rely on heating elements. In other words, the term "hot tub" is merely a naming convention, not a limitation. Functionally speaking, a hot tub can also operate in cold water mode.

Neglecting water quality management increases the risk of hot tub lung: • Insufficient disinfectant concentration or improper use; • Failure to regularly clean the filtration system; • Infrequent replacement of circulating water in the bathtub; • Failure to drain and dry the tub promptly after use; • Poor indoor ventilation, leading to aerosol accumulation.