Could be lack of cal/mag or start of a ph (absorbtion) issue. Calcium is needed by the other nutrients like N for proper absorption so the issue could be related. If you have been giving soluble npk but no calmag that would explain this but if you’ve been giving calmag all this time then it’s more probable to be a ph issue.
I've been running H.G.'s full line. Ive been adding 3-5ml/gal calmag at every watering. Is there any way to know if it's high ph or low ph that's the issue? I keep the ph of my water 6.2-6.8.
Two roi e680's in a 4x8 running at 60%. Soil: FFOF. 3rd week flower. CO2 1200ppm daytime termps 80-85, night time temps 70-75. RH 60%. Any other relevant info you want?