Coffee pots are not the only thing that suffers from hard water. Think of your water heater, other water using appliances and all the fixtures in the house.
Softeners come in various sizes, like vehicles, so they must be sized based on the job they have to do. So I suggest a correctly sized softener, with the correct constant SFR (service flow rating) required based on your family size, the amount of hardness, the number of bathrooms and the type of fixtures in them. That softener should have a Clack WS-1 control valve. For sizing info, visit the sizing page on my web site.