is this N def or mites?

do you mean keep the nute level the same throughout the whole grow? wouldn`t the nitrogen cause a lock up because as fer as i know they wont drink it as much in flower as in veg, and i do believe that nitrogen causes the most lock ups.
and dont be fooled by the 7.2. the extra .2 does make a difference. i cant recall if you are in soilor not. just curious how you took that reading.

Too much nitrogen will always cause a lock-out...Although plants still need nitrogen common day nutes very little...and basically gives what works....although what works is not always whatz best.... I use flora brand so i I alway add a lil be more nitogen then suggested and that cured my problem forever