I never added the extra Nopox because I found a big reason why my nitrates were rising despite the MB7: The addition of the bio pellet reactor changed my system flow due to the water displacement, and caused water to start flowing through the emergency drain, which I did not notice until a couple days ago.
Since I use a rollermat connected to the main drain, any water overflowing into the emergency drain is not filtered through the rollermat.
Since this situation causes such a big issue, I added a sensor (DSL_WL) in the overflow to let me know if the water level is approaching 1/2 inch of the emergency drain, and code to EMAILALM to notify me if it is CLOSED, so I can correct before this happens again.
I made flow corrections yesterday, and this mornings nitrate reading was down big:
I will be continuing with the heavy MB7 treatment for another week or so to analyze further now that this issue has been identified and corrected.