Start with 50 ml NP-BACTO-PELLETS for every 100 litres of aquarium system water and fill the filter media in the reactor chamber. Consider the operating instructions of the reactor. Double the amount after four weeks if necessary but DO NOT EXCEED 200 ml of NP-BACTO-PELLETS per 100 litres of aquarium system water. For the removal of nutrients and gas exchange a protein skimmer is recommended in marine aquariums