What and how much / how often are you feeding?
What is the soil?
Medinugs. Sorry for your opinion on soil. You made mistakes and condemned the soil for it? Sad.
Adding extra P&K at 2 weeks is a week to early first off! I would guess your problem was to much P&K to early, causing a P&K tox issue. That will give you a yellowing condition starting at the bottom in the stem leaves and progressing up and out the branching. Only a minor P&K shift till the start of week 4 of flower. Sounds like you used a not so good soil too. I mean did it have any bio's in it to start? Lime in the soil will only loose it"s buffering ability if all the living Bio's in the soil die off, as it has nothing helping it.
That can happen from guess what? Over feeding. Especially if your using a synthetic nutrient and jack that factor up if it's Urea based! Running an AACT tea in soil, even with synthetics is a GREAT way to keep those living bio's IN. Of course you can buy them in many forms too. Look at most nutrient makers lines,,,,,,,,they contain some form of bio's for the soil and the quality makers have them for all forms of soiless ! Running a zyme? That's living bio's!!!!
Ph'ing the run off is only telling you the pH of the run off! Any good soil grow will self Ph if you keep the grow in good health.