Master Clear Scale Defense is a liquid stain & scale protector designed to inhibit the build-up of calcium & mineral deposits along the waterline of the spa, as well as on the equipment of the spa & in the plumbing.  Used regularly, Scale Defense will help to keep your water looking great as it helps to prevent calcium & mineral build-up along your waterline, as well as in the spa itself.  Scale Defense will not alter your spa’s water chemistry & is ready to use, just add as directed to your spa.