NeoPlexª is a broad spectrum antibiotic effective against most external infections of both marine and freshwater fish. Used as directed, NeoPlexª will not discolor the water or damage the filter bed. It is well tolerated by invertebrates, although delicate species may be stressed. Contains neomycin sulfate DIRECTIONS: Use 1 level measure (included) to every 8 L (2 gallons). Repeat once a week for up to three weeks until symptoms disappear. Do not use UV, ozone, or chemical filtration during use. Remove with carbon before turning on UV. 10 g / 0.4 oz (Treats 800 L (210 US Gallons)