I have a 12 year old softener powered by a Clack WS1. The entire time it has been set up to refill the brine tank 2 hours before a regeneration begins. I would like to change this so that it refills the brine tank instead at the conclusion of a regeneration. I went into the set up and changed the setting from "PRE" to "POST". However, the brine tank currently has no water in it. Must I manually refill the brine tank after changing this setting or will the WS1 "prefill" one last time to compensate for the change in settings?