Your CSI is lower mostly because of the low water temperature, but if it rises to 80ºF or more you'll be close to zero CSI which is fine. On the other hand, I don't know if your pH will settle in to being stable at 7.7 or whether it will generally be lower. You might consider opening up your cover during the day to help heat the water and close it at night to prevent cooling from evaporation. Your pool water is a little below the average day/night temperature of 80/55 so exposing it so sunlight during the day should help to heat it.
As for evaporation and refill, you have a built-in automatic pool cover so like my pool you should have virtually no evaporation and refill. Also, the CH for water in San Ramon, CA as shown in the
Dublin San Ramon Services District 2014 Water Quality Report, Total Hardness varies from 123 ppm to 449 ppm. CH is usually around 70% of TH so could be from 86 to 314 ppm depending on the source. Historically more water from was from the State Water Project and was low in CH, but with the drought more water is taken from local ground sources so will be higher.
Not all water in California is high in CH because not all water is taken from groundwater well sources. Where I live just north of San Francisco, the
Marin Municipal Water District 2015 Water Quality Report shows TH from 68 to 111 where 75% is the former so the CH is around 55 ppm. Likewise, the
San Francisco Annual Water Quality Report 2014 (which is also water used for the mid-Peninsula) shows Calcium averaging 11, but in calcium carbonate units that is 27 ppm. It is so low because the water comes from the Hetch Hetchy watershed in the Sierras so is mostly captured rainwater with little dissolving of minerals from rock.