Intense rainfall can cause a large volume of water to enter the swim spa hot tub. This not only dilutes the chemicals but also introduces a higher level of contaminants. In such cases, the water may require additional treatment.

For most residential users, performing a shock treatment on a swim spa once a week is a common and recommended maintenance routine. However, the actual frequency is not fixed and can be influenced by various factors.

In reality, sunlight itself does not directly "lower" the pH of swim spa tub water; however, it can influence the water's chemical equilibrium through various indirect mechanisms, thereby leading to changes in pH levels under certain circumstances.

However, for a swim spa—which is subject to repeated use, elevated temperatures, and direct contact with the human body—the rate of water degradation is far more rapid than that of natural bodies of water. Without appropriate water quality control measures, the quality of the water will deteriorate very quickly.

Compared to indoor units, outdoor swim spa tubs are more susceptible to odor problems. This is because the outdoor environment presents a greater number of uncontrollable variables—factors that continuously impact the condition of the water.

Temperature is one of the key factors influencing the stability of chlorine. Swim spa tubs typically maintain a relatively high water temperature to provide a comfortable hydrotherapy experience; however, these elevated temperatures also accelerate the chemical reactions involving chlorine.