If you experience the following symptoms after using a hot tub, you should suspect bacteria in the water: • Skin rash, itching, burning sensation; • Folliculitis or pimple-like red spots; • Localized skin infection or pustules. These are often signs of a hot tub rash caused by bacterial contamination.

For people with heart disease, using a spa hot tub carries potential risks. • Patients with coronary heart disease; • Those with a history of arrhythmia or heart failure; • Those who have had a myocardial infarction; • People with pacemakers (must have their device's safety range confirmed by a doctor).

In unclean spa hot tubs, it often causes a skin condition known as "Hot Tub Folliculitis." This infection manifests as folliculitis, rashes, itching, and even pustules, usually appearing within 24 to 48 hours of exposure.

Regular spa hot tubs only maintain water temperature, while hydrotherapy spa hot tubs focus on the combination of water flow and air pressure. If you want to achieve a therapeutic or deep relaxation effect with a spa hot tub, a regular model is difficult to achieve, while a dedicated hydrotherapy spa hot tub is the true hydrotherapy equipment.

In a dry indoor environment with a temperature maintained between 15°C and 30°C, a spa hot tub can typically be left unused for 2-3 months without significant damage. If exposed to the outdoors, wind and sun will accelerate the aging of the casing and seals. Even with a dust cover, it is recommended not to leave it unused for more than 4-6 weeks.

The water temperature is typically maintained at 37–40°C. Full-body immersion causes peripheral vasodilation and accelerated circulation. This not only helps with overall relaxation but also improves nasal blood flow, gradually reducing swollen mucosa and alleviating nasal congestion.