Discus Trace™ supplies a broad range of trace elements demonstrated* to be necessary for proper fish health and growth. Unlike terrestrial animals, fish obtain nutrients from both their food and environment. Trace elements are normally depleted by utilization, oxidation and precipitation, thus it is important to restore them on a regular basis. Discus Trace™ contains only those elements actually demonstrated* to be required by fish. Guaranteed Analysis (Amounts per 1 g) Calcium (min) 2.40%, Calcium (max) 2.64 %, Magnesium (min) 0.792 %, Iodine (min) 0.1 %, Potassium (min) 0.1 %, Copper (min) 0.032 mg, Fluorine (max) 0.001 mg, Iron (min) 0.007 mg, Manganese (min) 0.002 mg, Selenium (min) 0.000006 mg, Zinc (min) 0.007 mg DIRECTIONS: Use 1 capful (5 mL) for every 80L (20 gallons*) once or twice a week.