Rust Spots on the leaves

100% with Spinnn on this one - you're showing a calmag deficiency but a calmag excess would likely represent the same way and quite frankly should be happening if you're supplementing a soil medium with calmag at 2 weeks. For reference and comparison - I'll supplement a nutrient neutral medium like coco with the same dosage of Calmag that you're using in a soil medium that should already have an abundance of it. If this is in fact fresh (and not re-used) soil then you're over-feeding calcium and magnesium and she's having trouble fighting that off. Recommendation would be to cease use of any further nutrients at all for the next 2 weeks or so. She should pull out of it and start growing normally. After that, limit any nutrients that your supplementing into the soil to every other watering at most. You generally won't need nutrient supplementation in a soil medium until about a month after sprouting - one of the reasons why soil is rather user friendly. Hope it helps dude.👍

Hi, it's Looks like calcium deficiency - but you using cal/mag. I hear about somethink like "Rusty Fungus" One time it's kill my small plant and i need to trow it away. But i dont pay attencion for this so much that time and that was outdoor.

PH or root rot would be my guess. At 2 wks she should recover and shed those leafs anyways.

It's looks likes what it should not be , I mean it's looking like a calcium deficiency but you are applying cal/mag so it should not be that. By the way your infos says soiless and you are growing in soil with a bio bizz light mix so as you'r bringing a lot of calcium in soil I'm pretty sure that it's a calcium excess that is leading to that rust spots everywhere on the lower leaves , if you do nothing it will spread to the upper leaves. Unless you are growing in coco or with Reversed Osmosis water then no need to add extra cal mag ( or that much ) with every watering as there is enough in the water / soil / nutrients you'll use to feed the plant. Also the 6.2 Ph is not that bad as the good ph range in soil is between 6 and 7 ph but if you can manage your ph I would recommend to keep it at the average aka 6.5ph