Salifert Oxygen Profit-Test Corals and marine fish require very high levels of oxygen concentration because of the low solubility of oxygen in salt water so it is very important to regularly test the level of oxygen present. The Salifert Oxygen Profit-Test is extremely fast, measuring oxygen levels in just a few minutes and is scaled from 2 - 14 mg/L. Sufficient for 40 tests. Can be used for marine, fresh and garden pond water Warning! Reagent O2-1 is irritating and contains a base. In case of contact with the skin wash with plenty of water. In case of contact with the eyes wash with plenty of water and consult a physician immediately. If swallowed contact a physician immediately. Keep out of reach of children. Not for consumption. Instructions: Add to the test cial 5ml of water. Add 5 drops of O2-1 and swirl gently for 20 seconds. Do not shake since this could change the oxygen content of the water too much. Add 6 drops of O2-2 and swirl gently for 15 seconds. Allow to stand for marine water 5 minutes and other types of water for 1 minute. Add 6 drops of O2-3 and swirl for 20 seconds. Allow 30 seconds for color development. Place the test vial on a white part of the color scheme and compare the colors by looking from above. An immediate color corresponds to an intermediate oxygen content. The values on the color chart are in mg/l (ppm) oxygen. Try to maintain in fresh water (aquarium of garden pond) an oxygen content of 8mg/l or higher. In marine water an oxygen concentration of at least 7mg/l is advisable. Some fish need higher oxygen concentrations.