If one is interested in studying closed systems, rGCMCD approach is not very convenient since it calls for the specification of the chemical potential of all ions inside the reservoir in order to perform the grand canonical moves. This requires a separate simulation of the reservoir in which Widom insertion method is used to obtain the chemical potential of all the ions. Furthermore, the calculation of the Donnan potential within the grand canonical formalism makes such simulations slow. Recently we have developed a new method for canonical titration simulations utilizing the surface Widom insertion algorithm that enables us to easily calculate equilibrium pH. In such systems, the traditional Widom insertion method can not be used, since at high pH there maybe few or no hydronium ions present inside the simulation cell, preventing us from accurately determining the chemical potential of these ions. The difficulty of calculating pH in canonical reactive simulations is probably one of the reasons for the widespread use of the incorrect RR-cpH algorithm in the soft mater and biophysics literature. The primary objective of this paper is to quantitatively explore the limitations of the RR-cpH algorithm. To achieve this, we compare the RR-cpH algorithm with three different methods: the surface Widom canonical reactive simulation, the rGCMCD simulations, and the pair insertion simulations for systems with high salt content. At high ionic strength, the