Leaf Zone Liquid Aquarium Plant Fertilizer Use one teaspoon for every 10 U.S. gallons of aquarium water. Repeat weekly. Promotes healthy growth of aquatic plants. Encourages lush, green growth. Special chelated formula for rapid absorption through plant leaves. One ounce treats 60 U.S. gallons of aquarium water. Supplies iron and potassium. Iron is rapidly lost, resulting in yellow leaves and poor growth. Pottassium is needed for photosynthesis. Product contains 3.0% soluble potash and 0.1% iron. Size: 16 oz