VMInnovations Swimming Pool Winterizing Chemical Treatment Closing Kit - Up to 20,000 Gallons Swimming pool winterizing chemical closing kit for up to 20,000 gallons 1 quart winter treatment ensures clear water for closing 1 quart stain control helps prevent and control algae stains and build-up 2 pounds non-chlorine shock kills micro-contaminants, algae, and pathogens 1 small floater will control deposits on pool surfaces during the winter months