Don’t let algae or harmful bacteria get in the way of having a good time in your spa or hot tub — go with Di-Chlor. This stabilized, granular chlorine is perfect for use in your spa or hot tub’s water. Once added, this product gets to work disinfecting your spa hot tub immediately. And, Di-Chlor will not affect your spa’s alkalinity, pH levels or create scale buildup in any way.