That looks kinda familiar. It's the timing. I've been getting that hard fade in some of my plants at about that same time. It looks cal/mag def, but it can't actually be that because in my case it's in the soil and it's in the right proportions. So ... WTF, right?
I have no idea yet, but I ran across some stuff about ammoniacal nitrogen vs urea, and there might be a clue in there. From the High Brix side, we give a good shot of Cat drench (ammonnia) to switch up the soil charge which shaves mineral ions off the adsorption sites. But the switch in soil charge also messes with the existing ion paths, and can produce that same heavy fade if the adsorption sites aren't full.
Might be a clue in there.
I have no idea yet, but I ran across some stuff about ammoniacal nitrogen vs urea, and there might be a clue in there. From the High Brix side, we give a good shot of Cat drench (ammonnia) to switch up the soil charge which shaves mineral ions off the adsorption sites. But the switch in soil charge also messes with the existing ion paths, and can produce that same heavy fade if the adsorption sites aren't full.
Might be a clue in there.