Technically speaking, most spa jacuzzi hot tubs do use ordinary tap water for filling. However, this does not mean that tap water can always be used directly without any treatment.

In fact, baking soda (sodium bicarbonate) is a common, fundamental regulating agent in water treatment. When used in appropriate amounts, it can influence the water's pH level and alkalinity balance. Consequently, people sometimes use baking soda when maintaining the water quality of their spa hot tubs.

Theoretically speaking, excessive chlorine levels can indeed be linked to water turbidity in a spa hot tub; however, this relationship is not a simple, direct cause-and-effect scenario. Chlorine itself is a transparent chemical substance; it does not directly cause water to become cloudy.

Under normal conditions, the chlorine odor in a spa jacuzzi hot tub should be relatively mild. If the water surface emits a very distinct, pungent odor, it typically indicates that the chlorine concentration in the water is likely elevated.