In The Swim Self-Floccing Spa Defoamer - 4 x 1 Quarts 4 x 1 quart bottles Self-Floccing spa defoamer prevents water foam on a long term basis Chitosan breaks down foam then flocs it together so it can be easily removed by your filter Spa foam is flocced together to be trapped during filtration Dosage: 2 ounces per 500 gallons