" I'll add some CalMag when I actually dare water. Right now I'm trying not to drown the roots so it's cat-and-mouse with too-dry conditions until we get some roots out there where the action is. "

Hmmm, unless that well water's very odd, judging from the ppm readings you can probably skip the calmag.

I add it because my tap water is ~120 ppm.
Just keep shakin' yer squirter whilst you water.

Aloha,
Weeze