Not sure I understand your number references? What type of denitrator do you have?
In general terms, denitrator equipment can take anywhere from 6-8 weeks to begin showing results. It takes time for the anaerobic bacteria to form and deal with the nitrates. With granular products they rarely show possitive results do to the fact they cannot be effectively housed in a low enough O2
Also keep in mind if this is a coil system or similar set up, the flow must remain at a trickle until you get no reading from the out port. If the flow is too strong/high in the beginnibg, too much O2
will be going through the system and prevent the growth of anaerobic/anoxic bacteria. You are basically cycling a coil system the same you would the tank. Once the cycle is done the flow through the set up can be increased and used as an effective means of denitrification in most cases.