Phosphorus is one of the main three macro nutrients (nitrogen, phosphorous, potassium: NPK) required by plants and can often become the limiting factor to growth in a ?ourishing system. Seachem Flourish Phosphorus is a safe solution (4,500 mg/L phosphate) of potassium phosphate that takes the guess work out of phosphate dosing. Unlike competing products that mix nitrate and phosphate in a fixed ratio, Seachem Flourish Phosphorus (being nitrate free) allows you to dose phosphorus according to the needs of your plants without the risk of overdosing nitrates. When used as directed, Flourish Phosphorus will enhance and accelerate the growth of aquatic plants without enhancing algae growth.Seachem Fluorish Phosphorus+ Phosphorus supplement for the planted aquarium+ a safe 4500 mg/l solution of potassium phosphate+ takes the guesswork out of phosphate dosingApplication of Seachem Fluorish Phosphorus:Use 2.5 mL (half a cap) for each 80 litres of aquarium water once or twice a week or as neede