Ultra Clear Blue. Excellent for ponds that safely colors the water blue. This is a organic pond colorant that not only adds a beautiful shade to your pond, but also protects your fish and plants from extreme sunlight by blocking harmful UV light. It is safe for decorative fish and aquatic plants. No toxic residues. Use 2 ounces per 1000 gallons. Can be used with other UltraClear products. 12 oz treats 6000 gallons, 32 ounces treats 16000 gallons, and 1 gallon treats 64000 gallons of water.