Sera oxygen test O2 to the reliable and exact determination of the oxygen content in the fresh and sea water. You can see the oxygen content of the aquarium water within minutes. Oxygen has a crucial function in aquariums and garden ponds. In addition to fish, which absorb oxygen through their gills, bacteria that break down pollutants also require oxygen to carry out their task. Oxygen therefore contributes significantly to good water quality. A lack of oxygen often manifests itself by heavy breathing at the water surface, but usually only then, when quick action is required. Packing contents sufficiently for approx. 60 test in fresh or marine water. Sera Oxygen Test+ monitor the oxygen level in aquariums and garden ponds according to scientific standards+ particularly important in case of high water temperatures or dense fish stocks+ oxygen dissolved in water is essential for all aquatic organisms, including filter bacteria+ complete kit with special vial, syringe, and evaluation cha