Hmmmm, that's odd, I wouldn't think you'd have to use their RTC kit either. I have several of their RTCs and they work fine with the Time.h and DS1307RTC.h libraries. I think I may have tried Ada's library in the past, and I don't remember any problems, but for whatever reason I just stick with Time.h and DS1307RTC.h. Time.h has a lot of functionality which I like. DS1307RTC.h also will work with a DS3231 (Chronodot).