Eheim CO2 long term test for the permenent direct measurement of the CO2 content in aquarium waters. Application: add approx. 1 ml aquarium water up to the marking of the filling level and 4 drops of indicator reagent in the CO2 endurance test unit and fix it in the aquarium at the pane using a suction cup. Compare the indicator with coloure scale and read the value. The indicator reagent (30 ml) is separately available.Also included are three 5 in 1 test stripes for the 5 most important aquarium water values: nitrite, nitrate, carbonate hardness, total hardness and pH.