Use Detail King Extractor Maintainer to keep tanks and plumbing free from soap, scum, and hard water build-up and to keep unit working to it's fullest potential. Regardless if you are mixing extractor soap in solution tank or not you need this product for the in-line heating system to work most efficiently. This product will "descale" the inner workings of the extractor plumbing for better performance. A busy detailing business should use this at least once per week. Gallon size.