With the Long-Term Test Correct you can measure the CO2 content of your aquarium over the span of 1 month.
The CO2 Special Indicator responds to the CO2 content by changing color: blue = too little CO2, green = ideal CO2 level, yellow = too much CO2.
The level of CO2 in the aquarium can be read directly from the six-colour scale in milligrams per litre. This provides an absolutely simple and reliable means of setting the correct CO2 supply level.
he CO2 long-term test Correct even allows you to monitor the pH value in your aquarium at the same time!