What is this stains?

As I know, It's deficit of Cal, just on the very early stage. The greener - the earlier. It would be harder to define by just first pic, because it could have been something different too, but on the second it also appears in shape of abrasions in the middle of the leaves. It also common, that it appears on the bottom leaves first. I'd suggest add CalMag, if you didn't add before, or raise it if you did. That leaves would not recover. But they'll stop suffering, and the others will be ok 😃And the plant should be growing faster. Despite this, leaves looks big and healthy 💪