Woher kommen diese Flecken?

p-deficiency symptoms Calcium can lockout P. Have you overdosed it with Ca? How much calsium is "all mix" contributing plus what you are adding? Since there's only 1 set of symptoms and looks fairly normal progression, i'd wager it's an actual lack of available P. pH would fuck up calcium before other things, so again, probably not pH-related. Need to rule this stuff out with common sense and take the most likely path. This one looks pretty clear-cut.

The spots look like early calcium or magnesium deficiency. With Biobizz Biogrow, calmag can sometimes lag. Try adding a small calmag dose even just a little bit will help. Check your pH too if it’s too high or too low, it’ll lock out calmag even if it’s in the medium.

I'm going from your profile and the nutrition you're using, I reckon you're in a living soil with biobizz nutrition. IMHO, there's no use in adding CalMag to a pheno that's not yet in bloom - unless you're using dead soil or another non-living medium. Given the pattern of the specks, I'd say she's experiencing a phosphorous deficiency. The leaves that have that pattern also have slightly burned tips. As such, I'd say your guess is in the ballpark, this was probably caused by too much CalMag at the wrong (imho) growth stage. As such I'd want to give two tips if you want: 1) No significant need to adjust PH if it's between the range of 5-7 2) No need to use CalMag until the start of bloom - it'll hurt more than it helps if you mess up the solution.

Based on the appearance of the leaves and your setup, this doesn't look like a CalMag excess, especially if you've been using it sparingly. Those dark, necrotic spots on the edges and tips of the leaves, combined with the overall yellowing between the leaf veins, strongly suggest a potassium deficiency (K) or a nutrient lockout instead. Since you're using Biobizz Bio-Grow, keep in mind that organic fertilizers heavily depend on microbial activity in the soil to become available to the plant. Even if your pH level is correct according to the meter, a slight fluctuation or salt buildup in the medium can cause essential elements like potassium and magnesium to be blocked. When potassium is blocked, the plant can't properly regulate water and nutrient transport, leading to those burned, crispy edges. I would recommend gently flushing the medium once with pH-adjusted water to dissolve any salt deposits, and then fertilizing again with a balanced schedule. It's also a good idea to check the pH of the runoff water to ensure it's in the optimal range for soil (around 6.2–6.5) so that the roots can actually absorb the nutrients. Happy Growing Growmie🌱