Good soil, are you in flower or veg? Calmag? Could be a lot of different things, mag deficiency, PH issue also possible. Do you have a picture of the whole plant. How widespread is the issue?
Is it not just limescale residue from tap water? Those white bits look they would scrape straight off of the leaves. Or maybe it's nutrient residue if you splashed some on the leaves while watering
Is it not just limescale residue from tap water? Those white bits look they would scrape straight off of the leaves. Or maybe it's nutrient residue if you splashed some on the leaves while watering
Good soil, are you in flower or veg? Calmag? Could be a lot of different things, mag deficiency, PH issue also possible. Do you have a picture of the whole plant. How widespread is the issue?