If the ferrule nut is tightened down but the tubing is not all the way through it, this can cause leaking around the tubing and ferrule nut.
If you are installing a new softener, make sure to pull on the brine hose (black tubing) that's connected to the ferrule nut at the venturi to ensure that it’s securely connected. Below you will find pictures of proper and improper installation. If it’s not installed correctly, the black brine hose will fall out of the ferrule nut when you pull on it.
Need to know: The ferrule nuts aren’t reusable when this happens because the ferrule is clamped down too far and the tubing won’t go through it. You’ll need to order a new ferrule nut. If you’re still under warranty, have your serial/model number handy and Contact Us for replacement parts. Otherwise, they can be purchased here.