Secondary disinfection

Secondary disinfection is the CDC Model Aquatic Health Code recommendation for any aquatic feature where toddlers and non-toilet-trained kids play, which includes essentially every splash pad. Most installations use medium-pressure UV; a smaller number use ozone injection. Secondary disinfection does not replace chlorine — it supplements it. The chlorine residual still does the bulk of the work in the tank and at the features; UV or ozone catches the chlorine-resistant pathogens that would otherwise survive a full recirc loop.