There are some brands out there boasting a “self-cleaning” feature to their hot tubs and swim spas which is confusing many consumers, making them think that they are maintenance free. This is simply no the case. First of all, hot tubs and swim spas are all self cleaning to some extent because they all boast filtration systems and many offer advanced water purification systems. Filtration system move the contaminated hot tub water thru the filters many times as hour in order to remove dirt, oils, and debris. Some do it better than others, none-the-less, they all do it. There are floating skimmer filter systems, there are pressure filter or cyclonic filter system, there are smaller weir filter system, and there are vortex filter systems. Then there’s the number of filters each spas has, the size of the filters, the placement of the filters (horizontal or vertical, and the type of filter used (anti-microbial material, pleated polyester, other). These filters are the first line of defense in what called the “self cleaning” phase. The second part of the self cleaning is the water management system which has to do with water sanitation. These systems can use ozone generators, ultraviolet light (UVC) purifiers, saltwater systems, mineral purifiers (ionization), copper purifiers, or a combination thereof. These water management systems are also not stand alone as they all require some small amount of sanitizer like bromine or chlorine with them to keep bacteria at bay. If you think about it there’s not way to regulate how effectively any one of these systems will work based on bather load. If bather load and bacteria level in the water are light then these systems may stand alone and be effective but if you introduce higher levels of contamination (think hot tub party or lots of kids) then these systems need to be supplemented with chlorine or bromine.