Pond Logic Twilight Blue maintains a neutral blackish-blue tint that is ideal for shading and protecting your pond without making drastic changes to natural pond coloring. Its powerful 4x concentrated formula allows each quart dye to treat like a gallon of competitive brands. One quart will treat up to 1 acre, 4-6 feet deep, making it extremely cost effective. We do not recommend using this product for water gardens 10,000 gallons or less.