Total Alkalinity (TA) – The First Step to Balancing Total alkalinity measures water's buffering capacity against pH changes; it can also be understood as the "foundation of water quality stability." • Ideal Range: 80–120 ppm. If alkalinity is too low, pH will fluctuate frequently; if alkalinity is too high, pH adjustment will become difficult.

·37°C~38°C: close to body temperature, relatively mild, generally recommended not to exceed 30 minutes; ·39°C~40°C: hotter, with a strong soothing and relaxing effect, it is recommended to control within 20 minutes; ·Above 41°C: higher risk, heart rate may increase, skin overheating reaction, not recommended to exceed 10-15 minutes