Swim in smooth luxurious water! Revolutionary product exclusive to BioGuard® and the first sanitizer made with SilkGuard® Technology. A unique additive that attaches itself to hard water components and metal surfaces, protecting against corrosion and staining. Leaves water extraordinarily soft and smooth. Kills bacteria and controls algae. Should be used with BioGuard® Care Systems: 3-Step, Once-A-Week 3-step.