Thanks for the input
I have 2 plants of the same strain in that box, they both get same nutes. And the other is green without any signs of purpleing.
Forgot to mention - I accidentally put too much epsom salts when they had a really bad magnesium deficiency... Actually, when I think more about it, all of my problems started after too much Mg. I flushed everything twice but problems still occurs: calcium deficiency (or lockout) is the worst one happening right now. Also I was getting dark spots (phosphorus deficiency) so I increased bloom nutes, and then purpleing started to happen. Lots of yellowing at the bottom leaves. pH were always in a good range. My plants were doing great until Mg incident, and now blooming is slow ...
Do you guys have any suggestions how should I complete this grow? Increase/decrease nutes, give more/less calmag? About 3 weeks left until harvest.
Btw, OldMedUser, thanks for advice. I should definitely increase N because I only gave them ~0.5ml/l of Biobizz grow couple past watterings.