CRITICAL CLONES

Hi all. PLEASE HELP! Im trying to figure out whats the problem with the leaves. It started around week ago. I was fighting with mites, but last two or three weeks it seems they are gone. And the mites was never there in a big amount. As you can see on last leaf detail photos, there is yellow spots (boundless) scattered irregularly all over the leaf. Most often these spots are at the edges of the leaf and at the tips. The bottoms of the leaves are all right. One can say it looks like overfeeding, but I dont thing so, as I feed them only half doses regarding to nutrient schedule. Thank you for any help or advice.