Flourish Trace, 2 L / 67.6 fl. oz. Trace elements for the planted aquarium Supplies a broad range of trace elements demonstrated to be necessary for proper plant heath and growth Trace elements are normally depleted by utilization, oxidation, and precipitation; thus making regular restoration of trace elements important May be used with Flourish; for best results use both Flourish and Flourish Trace 250 milliliters treats 50 US gallons for 2 to 4 months