Rendezvous Spa Specialties Sani-Spa Chlorinating Granules (1.75 lb) Rendezvous Spa Specialties Chlorinating Granules 1.75# Bottle Quick Dissolving, Fast Acting Compatible with Ozone and Mineral Purifiers 1.75# Bottle Chlorine Granules .5 oz per 500 gallons of water. Easy to use measuring cap.