There were signs of calcium deficiency (rust, stunting, lack of lateral branches). At the same time, the solution contained water 60ppm + calcium from GHF to 200ppm, raised the concentration to 300ppm, but the problem progressed. I decided to change the calcium, because this powder is more than three years old. After replacing the solution with new calcium, the problem immediately went away.
@SkunkleDamo,
before flowering, I changed 100% the solution once a week. for flowering, when it took 5 liters per day, I changed 100% of the bloom every three days, because the ph began to jump. it was on mineral fertilizers powder feeding. On simplex organomineral fertilizers, there is no such problem. although by day 10 it became worse to assimilate the solution (the ppm level up), but after replacing 2/3 everything got better again