Barley straw has been used for hundreds of years to promote clean clear water conditions in ponds and streams. Aquascape EcoBarley™ Liquid Extract is a pharmaceutical-grade, fermented barley extract that has been concentrated to give you a clean, clear pond. The added enzymes will help reduce pond maintenance by breaking down pond sludge and keeping filter pads cleaner. 8 oz. treats up to 5,000 gallons.