Treated for yellow leaf spot one more time and removed all leaves that were affected. Also preventively treated against insects with a bio spray before flowers really start showing. I really hope the yellow leaf spot will just leave my new growth alone from now on. The plant is definitely growing fast though.
@heizen, thank you but this grow actually completely went downhill after this point. What I thought was disease was more likely pH issues as my meter was giving wrong readings. I've started a new grow where I kept a flowering clone of this plant tho :)