The more I'm looking at phosphorus deficiency the more this is looking like it actually.
This goes back to my initial suspicion that there's a lockup in the coco coir - probably salt buildup since i skipped a day of watering and things havent been quite the same since.
Guess I'll flush them today before feeding and see how they do.
15 ml grow/10 ml
cal-mag/10 ml liquid kelp in 1 gallon of water at around 780-820 ppm because I was too lazy to bring it down to around 700.
6.2 ph.