Excellent question. The simple answer is no. You only need to change the hardness in the programming and you will be fine. The complex answer would take several pages, but considering this is a residential application and you have done the proper hardness testing, and you are maintaining below 1 GPG, the system should be fine. There are compensations we use for TDS, etc, but residential applications tend to have plenty of reserve to negate the need for complex equations. In large commercial applications, a 5% increase in efficiency can be significant, in a residential application, it is almost insignificant. How often will your system need to regenerate now? As long as you are over 5 or more days, you will still maintain considerable efficiency.