Co je špatně a listy?

Hey man, those little brown spots can be two things most of the time: either a small calcium issue, or the feed is running a bit hot / out of balance. The easiest way to stop guessing is to check your runoff EC. If your runoff EC is way higher than what you're feeding in, that usually points to salt buildup/ overfeeding, so I'd ease off a bit (or do a light flush) until runoff comes closer to input. If runoff is close to input, or even lower, then it's more likely calcium-related and you can try a small CalMag bump... from the pic she honestly still looks pretty healthy, a couple spots aren't a big deal unless you see them spreading quickly or showing up on new growth.