Hello, I've had similar issues almost every grow of mine mid flower.. although I have still had successful harvests each time I've found that most of the time a slurry pH test of the media as well as a runoff pH test put me out of pH range due to salt buildup in my media and a slightly acidic base media (peat moss).. Not sure if this is your issue but Id start with the slurry test at 1:1 media to water ratio using whatever water you'd use for regular watering (not feeding) generally dechlorinated tap or pH buffered RO and see if you're in correct pH range and then you can flush with pH buffered water to get you back to where you need to be as well as remove any buildup. But remember to hit them with a half or 3/4 dose of nutes the day after the flush to avoid severe issues there, may seem super overwatered for the first couple days but should recover much better and stronger. Hope it helps..
