i would def. recommend PH testing. i use a cheap aquarium ph test kit. costs maybe $4 and lets you know where you are at. the thing with PH is that you can be in the right range, maybe slightly high or low, but overtime this adds up. while your medium can buffer a little, once you are on your way off its just a matter of time before its all fully loaded up.
I am currently flushing an old medium that i will be reusing. I grew my plants in it and all was well, always feeding 6.4ph and ~500ppm. well when i flush that 2 gallon pot it all comes out at 1500ppm with a ph way off. as i feed neutral water it all gets back to where it should be.
point being, your medium will drift unless you watch what you are doing.
good luck.
PS: Where did you get the big bud from? I had some from Linda Seeds i believe, they just finished, beautiful turnout on the plant. really nice nugs, smells good, good consistency, good mix of frosty and compact.
I'll take your advice and start ph adjusting from now on! I got mine from a UK distributor called discount seeds. They were only cheap as I want more experience before I start shelling out on reputable seed banks. How long did the flower phase take roughly?