Yeah, I think I finally figured out what was going on.
The plants in my old dirt are growing awesome.
Plants in the new dirt I just made up, are doing terrible.
I PH tested the runoff from the new dirt...and holy jeeze was it high. Like dark dark green. So like PH 8 or worse.
So I mixed up some pretty acidic water, picked 2 of the worst looking plants, and over about an hour slowly soaked them.
Then checked the runoff. Light green, almost yellow. So right around 6.0-6.5. Right where I want it.
I have no idea why the dirt would be so basic. I've never used that brand of soil before that I mixed with the coco, so...who knows. What I do know is that I think it was so basic it was making the plants grow terrible.
I picked two as an experiment. If in 24 hours they are perking up and looking better, I'll do it to the rest of them.