What causes that musty hot tub odor? The root cause of those occasional musty smells when opening a spa is often misunderstood. These odors emanate from bacteria thriving on the spa’s surface above the waterline.
Here’s the breakdown: When individuals enter a spa, they displace water, causing the water level to rise temporarily. Upon exiting, the water recedes, leaving a residual band around the spa, typically 2-5 inches above the water line, termed the “tidal zone.” This zone retains water containing bacteria, no longer sanitized by the spa water. When the spa cover is closed, creating a warm, humid environment, bacteria multiply, leading to the musty odor.
Although some attribute these odors to the cover, its contact with spa water is minimal, making it an unlikely source.
303 – Mold & Mildew Cleaner + Blocker is the perfect product to clean and prevent bacteria growth in the “Tidal Zone”
