IMO, the principle and mechanize of a CR and denitrator are quite difference.
The flow rate of pump in CR is strong, water intake from top then push water via a pipe direct down to the bottom.
In the case of denitrator, the flow rate of pump is much lower, water intake via the pipe sucking water direct from bottom and the outlet of water stay on top. Bio balls or Sulphur media helps to blocks/prevents oxygen flow down to reach bottom.
See quote from Deltec http://www.theaquariumsolution.com/files/S...e%20Filter2.pdf:
"It is important therefore to understand that for the unit to work you must create a STABLE bacterial colony and if you allow too much air rich water into the reactor before the colony is stable then it will crash and you will have to start again from the beginning."
Hope you able to find a way to confirm this...