API’s Root Tabs are a necessity for avid aquarium enthusiasts. For tanks that contain live plant life, simply drop a tablet into the water. The tablets contain an iron and potassium compound that is essential for the healthy and lush growth of under water aquatic plants. These nutrients help aid the plant in developing a strong root system, which in turn, promotes healthy green leaves. Because aquarium plants lack the correct nutrient sources that are available to wild plants, fertilization is necessary.