macchie sulla foglia

Hard to tell from here what is going on. Your feeding is high enough so you can rule out potassium def. Might be ph issue, calmag def and or light stress. Try to check the ph of your runoff. And at the same time you can check ppm of runoff as well. You know the numbers if you grow in soil ph of runoff should be between 6 to 7.5. Ppm should be about the same as what you put in or less. Other issues might comes from your substrate what I see is 19% soil and 11% perlite ...what is the other 70 % made off??!! If you have mixed hydroponic medium like coco coir, peat moss (yes peat is soil less) clay pebbles like (Hydroton) those are all inert and needs to have a lower ph for growing. Does all affected leaves are at the top of the plant and close to the light? if so raise your light!