When growing using scrog method do I want to fill ...

Looks like you still have a lot of space to fill in before you would flip. Your issue with the purple leaf stems looks like a phosphorus deficiency combined with yellowing lower leaves which is nitrogen deficiency. From your photos it looks like the main stem has purplish red streaks running up it. A nitrogen deficiency can also cause purplish red leaf stems and streaking in the main stems. I would try increasing your A & B to give her more of what she needs. You definately don't have a Cal/Mag issue and you should drop that back to a normal dose so you don't cause any other issues. Your ph should be a bit lower at 5.6- 5.8. Good luck