What are this yellow spots? They are getting worse...

Hey buddy :-) . Can it be watered or fed too much? there is a very simple trick when you give water. Let it dry nicely, then lift the pot up and remember how easy it is. Then pour it and lift the pot back up and notice how heavy it is now. The next time you water, you will only do it again if the pot is as light as when you started. As a pure beginner, you can also use a scale and note the weight ፦). Keep carrying as before 👍 If you overfeed, I would proceed as follows. Best if you have osmosis water and mix the stale water for 24 hours (after 24 hours the chlorine has evaporated somewhat) to an Ec value of 0.2. Then add Cal / Mag until the Ec is 0.4. This is your source of water, so you can flush. At the next pour, start with a quarter of the feed dose.