BioGuard SilkGuard Complete 3" Chlorinating Tabs - 25 lb Bucket. New BioGuard SilkGuard Complete Chlorinating Tablets. BioGuard's SilkGuard technology does more than your average white chlorine tablet, such as: Kills bacteria and controls algae, makes water soft and smooth, prevents metal staining and corrosion, softens water and reduces scale formation. BioGuard SilkGuard Tablets also have SUNSHIELD which protects chlorine from sunlight, so you use less. Saving you money.