This happens when the chlorine or bromine level in a hot tub is kept much too high. You know how you use ‘clorox’ bleach to get your clothes white again, well, chlorine and bromine at high levels does a great job of ‘bleaching’ your swim suit. Your hot tub should never have this high level of chemicals and if the hot tub at your gym or at the hotel has levels of chlorine this high, you might not want to get in. 🙂