Purple stems are normal. All my plants have some sort of purple in the stems and/or branches.
Calcium def should show interveinal chlorosis. It does not. Either a P def or excess. Possibly due to PH.
Welcome @ShellyB …Yes it can be a puzzle at first and having leaf problems IS frustrating…Ive been growing outside since Oh…2020 I guess … So while I’m not exactly a novice I’m no expert either…We learn as we grow… 
Im having issues @ times with leaves too…The leaf symptom chart helps but to me they all start looking like the same problem…
The guys/ladys of ILGM are very supportive Good luck!