The real source of the roughness: Calcium carbonate deposits The rough feel of a spa hot tub is usually caused by scale buildup. Scale is mainly composed of calcium carbonate (CaCO₃) or magnesium carbonate (MgCO₃), minerals that come from tap water.

Low-calcium water lacks protection for metals and is prone to slight acidity. Long-term use will corrode nozzles, pipes, and heating elements. Metal corrosion not only shortens equipment lifespan but can also lead to metal dissolution in the water, affecting water quality safety.

The response of bacteria to temperature is not a simple "live or die" situation, but a gradual process. Below 40°C: Bacteria can still exist actively. 37–40°C is precisely the commonly used temperature range for many spa hot tubs, which means that: Normal operating temperatures cannot kill bacteria.

The ideal energy-saving temperature for a whirlpool hot tub should be maintained between 34℃–37℃. This range ensures a comfortable spa experience while avoiding unnecessary energy consumption. If the equipment is operated outdoors or in cold climates, the minimum temperature can be increased by 1–2℃ to prevent excessive heat loss.

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.

If your spa hot tub has the following characteristics, it is not recommended to use it as a shower: • The bathtub is made of thin acrylic walls, which are not suitable for standing; • It lacks an anti-slip bottom or safety handles; • Electrical components are exposed or close to the shower head area;