what does a denitrator do
By Tony Griffitts. A denitrator is a biological filter that removes nitrate (NO 3) from the aquarium. A denitrator filter uses anaerobic bacteria to brake down nitrate into nitrogen gas (N 2), which escapes into the atmosphere, the result is nitrate free effluent.hen you first set up the filter run the aquarium water through it at a swift rate for about 2 week. This will give bacteria time to colonize the filter. After 2 weeks cut down the filter flow rate to about a drop or two a second. At this time, start to add about 5ml of bacteria food a day to the filter.