Brown Spot Help

[sandune]

Basement 4x4 tent. 7 gal cloth bags. White Widow fem photo. Stonington Blend soil and nutes on their schedule. My tea 2x monthly. 8 weeks from sprout. Average 74 degrees, 65% RH. H2O pH 6.1, well water. 16/8.
Spots are on underside also. No bugs other than a few gnats.

Should I be worried?

[MrPeat]

It looks like the start of Cal-mag deficiency.

[Dclark]

I second what @MrPeat said brother

[sandune]

Thanks. Heading to the greenhouse now.