Pond Logic 4x Concentrated Nature's Blue Pond Dye, 1 Quart Enhance the aesthetic appeal of your pond with blue coloring Treats like 1 gallon of other dyes 4x Concentrated Pond Dye for Ponds & Lakes, One quart treats up to one surface acre 4' - 6' deep. No water use restrictions and is safe for people, pets, fish, waterfowl & wildlife. Can be used at all water temperatures. Protects against troublesome UV sunlight