Aquarium water usually contains too little carbon dioxide (CO2) as it has already been extracted from the tap water at the waterworks. In addition to light, nitrogen, phosphate and trace elements, etc., the most important nutrient for aquarium plants is CO2 and, the stronger and healthier the plants, the less chance algae has to grow. Plants also produce more of the oxygen that fish need to breathe and CO2 also regulates the pH values in the water, when dosed correctly. Complete with accessories, including: Precision pressure reducer with manometers and precise dosing valve for reusable systems 360° rotating hose connection CO² specific safety hose, pressure resistant, 3m, Ø 4/6 mm CO² safety diffuser including bubble counter and non-return valve for effective CO² dosing 5 x water test strips for analysis of the initial water values CO² long-term test and indicator reagent for permanently measuring of the CO² content in the aquarium Safe and toolfree installation Optional accessories (not included): CO² magnetic valve (night shut-off) Made in Germany 3 years guarantee