This paper elaborates the problem of temporal unity for dynamic presentism and diagnoses the source of that problem in the dynamic presentist’s discarding the traditional C-series in its avoidance of McTaggart’s (1908, 1927) A-series paradox. This C-series provided the fixed structure of time which the transitory aspects of time then followed, and thereby unify those transitory aspects. It then considers ersatzer presentism as an ostensible solution to the problem of temporal unity by providing a new abstract C-series (namely an ersatz-B-series) (...) for dynamic presentism. However, after a closer examination of the details of this proposal, it is found that the ersatz-B-series itself needs to be temporally variable to capture the transitory aspects of time that it is meant to track. Consequently, it cannot provide the fixed structure of time required to unify the transitory aspects of time into a temporal series. It is therefore suggested that dynamic presentists look for a more course-grained determiner of temporal progression to construct the presentist-friendly C-series required to unify their transitory aspects of time. (shrink)