Leaves problem

Here's how to tell if it's septoria... if you rub the spot and it feels fuzzy or black stuff comes off on your fingers, you've got a fungus. What I'm seeing is NOT a deficiency of either calcium (the browning would not be perfect little circles) or magnesium (again, it would NOT show up as perfect little circles and the color would be pale, not brown) so cal/mag is not going to do anything for this problem. If this were my grow, I would be researching different kinds of fungus issues... perhaps it's septoria, perhaps its another type of fungus... but that's the direction I would be heading in if I were you... It would be helpful to all of us (including yourself) if you had a diary for your grow... gives us a lot more important information to reference when we're trying to give good advice! Good luck!

She needs cal-mag, 1 tsp per gallon of water twice a week during veg. 2 tsp per gallon during flower.

I don't think septoria starts in the middle of the leaves. Any infection wouldn't do that , to me it seems lik she need some manganese or calmag.

Looks like septoria leaf spot. which is a fungal infection. Usually starts on the lower branches and works up. each spot will slowly get larger and then after a week or so they "fruit" and spread there spores.