Depending on your air pump and stone setup your water might not be moving enough to keep the nutes from binding with each other. For example I run 2x 10" air stones with a 4w airpump for each of my buckets. This is about the lowest amount of air I get can get away with and not have issues with mixing.
Also when I mix I leave between 15-30 minutes between bottles of food (micro, gro, bloom) Not as much time between support nutes (floralucious, flora nectar, diamond nectar, etc…). Things like armor si and calmag i add a day or so off schedule from the main feeding.
But mostly I think it was reducing the ppm theses days I max out in bloom around 1500ppm. And I don’t flush unless I run into a issue.