JBL ProAquaTest CO2 Direct Carbon Dioxide Test

JBL ProAquaTest CO2 Direct is a drop test for measuring the carbon dioxide (CO2) content of freshwater aquarium water directly.

CO2 is one of the main nutrients for aquarium plants, but too much of it can be dangerous to fish. Regular testing helps keep the CO2 level matched to stocking, lighting and water movement.

The test works by colour change. The number of drops multiplied by two gives the CO2 content in milligrams per litre. The manufacturer recommends 15–35 mg/l for a community freshwater aquarium and 20–35 mg/l for a planted aquarium with few fish. For Lake Malawi and Tanganyika aquariums the manufacturer recommends 4–10 mg/l.

Stand both tubes with 20 ml of sample water on the colour card and add 5 drops of reagent 1 to the tube on the white field. Then add reagent 2 drop by drop while mixing until the colour turns pink.

The set includes reagent 1, reagent 2, two test tubes, a syringe, a colour card and instructions.