There is one thing that I don't believe you took into account but you didn't mention that the roots kept growing and like we say the bigger the root the bigger the fruit right? I may take a few days longer but hell I push them as long as I can as long as I'm not seeing any herm or discoloration...
Its definitely ph and its because your having to water more and your plant isn't getting the iron/calcium it needs. You should get a solution that has edtA iron calcium ect... I did the same thing when I was learning.