I've gone through your journal and I will confidently say this is textbook root aphid infestation damage. Brew a neem meal/kelp meal tea 1x/week at 1/2 tsp neem meal and 1/4 tsp kelp meal per 1 gallon (bubble for 24 hrs) then dilute to 5 gallons and use as a soil drench. Alternating this tea with other organic IPM treatments will take you to harvest without much further damage but it won't eliminate the problem.
pH swing between 5.5-6.5 in your medium is not the reason for your issues.
You must to address the pest situation in your grow medium. This explains why no solutions have worked thus far, and nothing will continue to work for you if you keep treating the problem as if your percieved deficiencies/imbalanced element levels and/or pH is the cause.. If anything all the "flushing" you've been doing has been delaying the damage slighly - do you notice more "deficiencies" appearing as the pot becomes more dry? Textbook root aphids.
To clarify myself... yes, you are getting deficiencies. However the deficiencies you see are resulting from root aphids sucking the nutrients out of the roots, and also taking the nnutrients from the medium before your roots are able to encounter it. In both mechanisms they block your plant from uptaking what it needs.
Just an idea for you to think about, I could be wrong, but I'm 99% sure this is your issue. Hope this helps.
I don't think I have pest in my medium... But maybe that is the case why this happens? I don't water that much and we have winter here so no pest outside they come in summer.. I do nothing more in my medium I don't want more problems :-( I have neemoil but I never water with!
