Hi mate, I notice you had a few yellow leaves around week 2 of flower. What did you do to combat this? Also do you PH your water as your are using BIO? My shop told me not to PH the bio stuff even though the PH meter reads around 4.5-5 after mixing nutes. I have a bit of yellowing on the bottom and going to try dressing top of soil with Worm castings.
@snwaddct,the biocanna line wants a ph below 7 surely then the ec adjusts itself I think you have an electro-coductivity problem I have not done anything to combat this problem I only added calmag to the solution, also if the leaves are the most low and old it is normal for them to turn yellow