Brita water pitchers don't filter out a lot of solids in well water that can cause nutrient lockout. Pur filters filter out much more, and I have to change filters just every few weeks. I am thinking now, this whole issue started with the water. I've never used zero filter. But, I know I have success with the Pur. My well water has solids so bad, that every 2 or 3 months, I even have to take the cold water supply to my washer loose and clean that fine screen.
If that is what has happened, then your yield is really gonna suffer, but get a Pur or Zero (if as good) and just continue and we will all advise as it goes. :cool: