Reef Trace supplies a broad range of trace elements demonstrated to be necessary for proper reef health and growth. Trace elements are normally depleted by utilization, oxidation and precipitation. The latter two processes occur more rapidly than with other micronutrients. This makes it important to restore trace elements on a regular basis. Reef Trace may be used alone or in conjunction with Reef Plus. Best results are obtained when both are used. Reef Trace is nitrate/phosphate free. DIRECTIONS: Use 1 capful (5 mL) for every 80 L (20 gallons*) twice a week.