Phosphorus is one of the three macro nutrients (NPK) required by plants. It is a component of ATP, NADP, nucleic acids, and membrane phospholipids. Phosphorus is mobile in plants; this means that the plants divert these nutrients from older leaves to newer leaves. Thus, deficiency symptoms appear in older leaves first. Deficiency symptoms include dark, dull, or discolored leaves. Activate is a concentrated (6,000 mg/L P) phosphorus source. When used as directed, Activate will enhance and accelerate the growth of aquatic plants without enhancing algae growth. Activate is made with potassium salts of various phosphates, and is therefore a source of potassium as well. It contains 8,800 mg/L of potassium.