Sir...It is time to flush. Give it a week of flush, and then add nutes again. You keep treating problems, and not allowing sufficient time for the plant to adjust and let you know that you fixed the issue.

Your PH level is waaaaay to low for these girls. Your PPM is good for veg (but the new grow is rather light)...This makes me concerned for your overall PH stability due to the fluctuations. This will cause the plants to get the copper spots...yellowing and burnt tips etc.

To put it bluntly, you are suffering from lockout. Flush your res...give it a 3 days to one week of flush...and then add new water and nutes. Instead of looking for an explanation, you should be eliminating the variables.

Good luck...and I am sure they will come out of this funk! :jointsmile: