Geochemical modeling is used to understand water-rock interactions that occur in the sedimentary basin. Activities of aqueous species are usually calculated using the Davies equation, Debye-Hückel equation, B-Dot or Newton-Raphson. We perform a comparative study of geochemical speciation using three different software: PHREEQCTM, Geochemist's WorkbenchTM (GWB) and GEODELING (own code). Details of each software are carefully analyzed, taking into account the distribution, mobility, and availability of chemical species in geological environments. We can observe very similar results in speciation when working with low-temperature systems. GWBTM, GEODELING employ an integrated system to define when to use Davies, Debye-Huckel or B-Dot equation, according to the value of the solution ionic strength. The utilization of GEODELING allows comparing the results with software GWBTM and PHREEQCTM with a high degree of acceptance for low temperatures. Soon to high temperatures, we need to be cautious in their use.