Sanitizer - use 2 oz. per 1 gallon of water. Antioxidant and bactericide - use 1/4 teaspoon to 6 gallons. Dissolve sulphite in warm water before adding. Use 50 grams of sodium metabisulphite to 4.5 litres of cold water and wash your equipment in the solution. Allow equipment to stand for 1 hour to dry then rinse with clean cold water.