The fundamental reason for black substances flowing from the spa jacuzzi tub nozzles is that: The internal circulation system of the spa jacuzzi tub is constantly in a humid, warm environment rich in organic residues, a natural breeding ground for biofilm, mold, and impurities.

Correct order: Add acid first, wait for the water to fully mix and circulate, then add chlorine. Specific steps are as follows: 1. Test water quality parameters 2. Add acid (pH adjuster) 3. Add chlorine (disinfectant) Never add acid and chlorine at the same time or in the same area!

The answer is yes. Low pH in swim spa hot tubs is not only harmful to the equipment but can also irritate human skin and eyes. When the pH of the water is below 6.8, the acidity can irritate the conjunctiva of the eyes, causing redness, tearing, and even a burning sensation.

Researchers and health experts generally believe that spa hot tubs do not directly "cure depression," but rather indirectly alleviate depression-related symptoms by promoting relaxation, improving sleep, and lowering stress hormone levels.

Immersing your head in a spa jacuzzi bathtub poses several risks, including microbial infection, chemical irritation, physical injury, and suffocation. Even if the spa jacuzzi bathtub is sterilized, direct head contact with water can still cause health problems.

Chlorine is the most commonly used water treatment chemical and can kill most bacteria, viruses, and algae. Common chlorine sources in swim spa hot tubs include: • Liquid chlorine • Chlorine tablets or granules