The correct water values in the aquarium depend on the initial water, the fish stock and the existing plants. Even if the water looks clear, it may be polluted. With poor values, diseases or algae can form in the aquarium. For a healthy aquarium with near-natural conditions, regular control and adjustment of the water values is important. The JBL EasyTest strips serve as an orientation test here. The most important water values at a glance. The following values can be determined in the quick test: Disinfectant in tap water: chlorine test; Acidity of the water: pH test from 6.4 to 9.0; Stability of the water: KH test from 0 to 20 °dKH; Total hardness of the water: GH test from <1 bis >21 °dKH; Toxic nitrogen compound: NO2 from 0 to 10 mg/l; Cause of algae: NO3 from 0 to 250 mg/l; Easy application: The application is very simple: hold the test strip in the aquarium and move it back and forth for 2-3 seconds. Take the strip out and hold it horizontally to let the water drip off. After about 60 seconds, the values on the test strip can be compared to the color scale on the package. Store test strips in a cool, dry place. Always remove only the immediately required number of strips.