Hi buddy ;-) 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.