Suggestion: Cut nutes for a couple of feedings, do the regular waterings too. It's soil, they'll be fine, and you've been using a bit. Flushing with pHed water should help. Measure the pH of your runoff -- note that you will need a pen as strips are nigh impossible to test runoff with since it's not clear.
I don't know that it'll fix everything but it seems like a solid first step.