Seachem 19236 Flourish Supplement for Planted Aquarium, 16.9 fl. oz./500mlFlourish is a comprehensive plant supplement for the natural freshwater aquarium. It contains a rich assortment of important micro elements, trace elements and other nutrients. These include calcium, magnesium, iron and other important elements that have been shown to be beneficial to aquatic plants. For macro element (NPK) fertilization, use Flourish Nitrogen, Flourish Phosphorus or Flourish Potassium as needed. Flourish is safe for invertebrates