JBL ProAqua Test Easy 7in1 quickly and simply identifies the 7 most important water measurements in the aquarium and garden pond as an orientation guide. The nitrate (NO) and nitrite (NO) values indicate whether the biological cleaning processes are functioning efficiently. CH (KH) is important to stabilise the pH level. TH (GH) indicates whether the water contains too few or too many minerals. The Cl2 measurement shows whether the mains water contains chloridem, which is harmful to fish.JBL ProAqua Test Easy 7in1 contents: test strips EasyTest 7 in 1 on colour scale and CO2 table. Contents: 50 test stripsEasy to use: Move the test strip in the water for 2-3 seconds. Remove the test strip. Let the water drain off sideways. Compare the test strip with the colour scale on the packaging after 1 minute. Read off the CO2 value in the table -done!