WATER BASED silicone formula. USE IN: Swimming Pools, Spas, Hot tubs, Decorative Fountains & Ponds DOES NOT disturb water chemistry. DOES NOT leave an oily residue or cloud the water. SUPER concentrated Defoamer. Pool & Spa Defoamer is a concentrated liquid with a special water-based silicone formula to knock down foam in pools, spas and decorative fountains. It also works to prevent the formation of foam without disturbing the water chemistry or leaving behind an oily residue. Directions: For Swimming pools: Pour 4 ounces directly into pool skimmer or intake filter. For Spas and Hot Tubs: (up to 750 gallons) Add 1-2 ounces into water. For Decorative fountains: Add 2 ounces per 10,000 gallons of water