Your water supply is very hard. At 11 days you will exceed the capacity of the the softener using 200 gallons each day. This means you will start to break hardness through. I would recomend to use 70% of the rated capacity as the limit. Try a 7 day regeneration and if you notice your water not maintaining it’s softness then you can always go to a 5 or 6 day regen. Please read this article it will explain the practicle usage of water softeners.
Respectfully David F. Walling