Flourish 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 plantsr for macro element npk fertilization use flourish nitrogen flourish phosphorus or flourish potassium as neededr directionsr use 1 capful 5 ml for each 250 l 60 gallons once or twice a wee