With Tetra 6in1 test strips, aquarists can check six key water values, namely the pH value, the carbonate and total hardness, as well as the nitrite, nitrate and chlorine content, both quickly and simply in one easy step. This method means that less dedicated aquarium owners can monitor the water values with the minimum amount of effort. Conversely, aquarium enthusiasts can use this method as a preliminary test before deciding which liquida tests need to be conducted. Further improvements have been made to Tetra 6in1 strips     they now keep for up to three years