Flourish Potassium™ contains 40,000 mg/L of potassium suitable for the natural freshwater aquarium. Potassium is an important element that is needed by all plants. In a thriving planted aquarium it can become the limiting factor to growth if it is depleted. Flourish Potassium™ is an integral component of Seachem's plant products and is recommended for use with the entire Flourish™ line as well as our Flourite™ gravel. When doing water changes, use Equilibrium™ to set your initial potassium concentration. Contains no phosphate or nitrate. Flourish Potassium™ will promote vigorous plant growth while not enhancing algae proliferation. A 250 mL bottle will raise the potassium level by 10 mg/L in 1,000 Liters (250 gallons).