33oz bottle. Spa Purge from Natural Chemistry attacks the root cause of most spa maintenance problems- the buildup of non-living organic waste contamination. Oils, lotions, cosmetics, hair products, and other non-living organics build up in spa water to produce cloudiness, unpleasant odors, and foaming. These contaminants collect and build up in spas, circulation systems and filters. By purging the spa plumbing, you can improve water clarity and reduce the amount of time and effort needed to maintain your spa.