Ferreal + Spureal 250 ml concentrated iron fertilizer for aquarium plants, Aqualine Buschke. Ferreal is a combined compound containing iron and further essential trace elements such as manganese, molybdenum, boron, zinc, and cobalt that are essential to aquatic plants. Ferreal is rapidly assimilated by the plants. If used regularly, it promotes plant growth and discourages yellowing of the leaves. It gives the colors of the plants an enhanced brilliance. 250 ml for 375 gallons.