What time does the filter backwash?
A 2 cuft softener using regular mesh resin and 18 lbs of salt regenerates just over 48k of capacity. How much capacity do you need?
Eighteen lbs is 6 gallons of water. Depending on how much salt is in the tank, the water level will vary. So why do you think there's too much water in the brine tank? The water level stays the same except for going up and down with the volume of salt in the tank except during regeneration. The brine is sucked down to the air check height and then as the last step on the 5600, the water for the next regeneration is put back into the tank.
You filter should backwash first at say 1 am or 1:30 am if it is backwashed only, not regenerated, and then the softener at 2 am; the factory setting if the time of day is set correctly. If the filter control doesn't' allow a different time for the backwash/regeneration, lie to it and set it from 30 minutes to an hour fast; so it gets to 2 am sooner.
Check the water level in your toilet tanks and make sure they all shut off at the Water Level line; usually an inch below the top of the overflow tube. Either the tube or the back of the tank will have the water level line on it.
Gary
Quality Water Associates