Fastberry auto

I'm using Plagron Bat Mix soil and adding 1 liter every 3 days of RQS Easy Bloom tablets, but when growing with Biobizz All Mix, I never had these problems.

I'm guessing you're going too heavy on bloom nutes, which locks out calmag and micros.

Goin off what UK420show said, it's always handy knowing the hardness of your water. Hard water has loads of calcium and soft has none or next to none. In the uk where I am it's hard, so I never add calcium all grow. If it's hungry, I think it generally starts draining lower leaves, light issues start above. Where did you take this leaf from and where did you first notice it? Google your water company water quality, if it's available, which it should be, where ever you are.

Hmmmm a toughy my opinion would be to check her PH as a start. If that's fine I would look at her cal mag intake maybe too much for her. my 3rd guess would be a lack of oxygen to the root system the only reason i say this is I have similar symptoms when my pumps go off in my dwc buckets. anyway these are all opinions and should not be taken as law take a look at a leaf chart and try match up the symptoms to that always helps :)