Flourish Potassium contains 40,000 mg/L of potassium suitable for the natural freshwater aquarium. Potassium is one of several elements that are vitally important to maintaining a vigorous level of growth in a planted aquarium. Potassium can become depleted in a rapidly growing system or when the source water has a low mineral content. In these cases potassium could become the limiting factor to growth. Use Flourish Potassium to prevent potassium depletion and maintain the highest level of growth. Flourish Potassium is an integral component of Seachems plant products and is recommended for use with the entire Flourish line as well as our Flourite gravel. Contains no phosphate or nitrate.