Unfortunately my problem sort of resolved itself since the effected plants were boys and they are no longer part of the crop :clap:

Did flush the one remaining problem girl with just plain water with PH raised to 6.5 for three waterings. She is now on a special diet of Grow with a after mixing PH of 6.5 and a TDS reading of 531 and is flowering nicely

The remaining plants are all doing fine and are also flowering. Although I am not really happy with their stem size am hoping that the stems will become thicker as they progress to buds