Clorox Spa pH Down lowers pH in spa water making it more comfortable for swimmers preventing cloudy water and protecting your hot tub equipment. A spa pH decreaser like this one is just as important as maintaining pH levels in a pool. If the pH falls outside the recommended range water will cause irritation and can damage equipment. Since the spa exists to help you relax and enjoy time off it makes sense to keep it balanced so it doesn t irritate the people soaking in it. Use Clorox Pool&Spa Multi-Use Smart Strips to test your hot tub. It will tell you if you need a hot tub pH decreaser like this one to keep it balanced. It will also give you guidance on the sanitizer levels which is important for killing harmful bacteria. Hot tubs are a perfect place for bacteria to grow so keeping your pool sanitized and shocked regularly is critical.