When installing the drain lines from your main resin tank, as well as brine tank overflow, you want to keep in mind these are gravity-fed for the most part, so they will need to be as level or low as possible coming out of the tanks.
If you need to go up above the tank's head, you want to keep it as low as possible, less than 12" typically, to avoid any complications. Please give our tech support team a call if you have any questions about this, we are happy to help.