Salifert Dissolved Oxygen Test Kit Corals and marine fish require very high levels of oxygen concentration because of the low solubilit The Salifert Oxygen Profi-Test is extremely fast, measuring oxygen levels in just a few minutes and Sufficient for 40 tests. Can be used for marine, fresh and garden pond waterUL&gt;Warning!B&gt;Reagent O2-1 is irritating and conta Add to the test cial 5ml of water.