Hey there, bro! In case of substrate settling, it's recommended to bring its level back up to the early mark, gently fluffing the top layer (1 - 3 centimeters) of the old surface beforehand, preferably doing this carefully so as not to damage the roots at the surface of the substrate. 👌😇👍 Usually, substrate settling is caused by aggressive watering; maybe the idea of using drip irrigation will help you in the future to avoid washing away or settling of the substrate. 😉 Good luck, bro! 👋