Bottom line if you flocculate ...

Bottom line if you flocculate particles too much and they become to large, then you open yourself up for shearing the big particle and leaving straggler floc carryover.  Particle size should be almost homogeneous if you are flocculating correctly.  You gain experience by watching this in the mixing areas and observe the laminar areas to see the clarity of water from the immediate settling.  The water pool above the particles showing clarity and all the floc particles look about half the size of an old pencil eraser.  An art for sure.  If the water is clean enough you can explore an instrument measuring zeta potential and set a sweet point that the coagulant adjusts while the flocculant normally stays constant.  Once you have 2 variables, it becomes more complicated.  If you are tired of going out and checking on the mix zone for proper flocculation, we install led lights and a camera to remotely dial in the chemistry.  Works well when you can’t be live to “feel” it.  Sean