not so much a need to exactly determine what the exact def is because usually it is going to be a combination the real observation needs to be what part of the plant?
older growth or newer growth damage should be the first and easiest way to determine the dir the def is going
most of your damage is in newer development as to where potasium and P whould have first strongly shown up but you have a combination of def progressing from combination of zinc to slight start of mag and the looks of some nurfient burn added in the mix?
you flushed use distilled or R?O or filtered water like rec in other post
your water is residually building up and forcing lockout little by little