Brown leafs

Only one plant has those symptoms

They on first week of Flo, I use Biobizz Grow 1ml/L, Calmag 0.5ml/L, Biobizz Heaven 2ml/L, Rhizotonic 2ml/L, Biobizz Bloom 1ml/L, Topmax 1ml/L, Ph 6.6

Espom salt for mag sulphate + calmag. Had that very issue on week 3 of my super lemon haze soil grow. Good luck.

Burning from feeding too much or too often, or maybe both.....

Oh goody... no diary. Join the community, mate, and start one - we all want to help but without information, we're flying blind. It's like calling the doctor to say you've got a rash and asking what causes it... How old is she? What's the grow medium? Indoor? Outdoor? What nutes are you giving her and in what amount? What's the PH level? What are the temps? What's the humidity? This looks like it could be a zinc deficiency - but that is usually only caused by a PH that's out of range... zinc is absorbed only when the PH is between 6.0 and 6.5 in soil - out of that range, you could feed it pure zinc and the plant wouldn't take it... if you correct the PH level, the problem will go away although the damaged leaves will not recover... it is NOT a calcium deficiency so ignore any advice to add calmag... without a diary, we don't know if you're not giving her something she needs or you're giving her what she needs but she's unable to absorb it because of the PH.... Good luck