Pure Blue is a highly concentrated liquid water clarifier. Through the process of ‘agglomeration’, Pure Blue can clear cloudy hot tub water and restore its sparkle. Borrowed from the swimming pool industry, this formula is designed for hot tubs to coagulate, or gather together suspended micro-particles in the water. It forms masses large enough to be caught by the Microfilter. The regular use of Pure Blue as a preventative measure, will help keep water clear and sparkling.