porousMedia4Foam is a package for solving flow and transport in porous media using OpenFOAM - a popular open-source numerical toolbox. We introduce and highlight the features of a new generation open-source hydro-geochemical module implemented within porousMedia4Foam. It opens up a new dimension to investigate hydro-geochemical processes occurring at multiple scales i.e. at the pore-scale, reservoir-scale and at the hybrid-scale relying on the concepts of micro-continuum. The package is designed such that only the chemistry part of the solver is handled by an external package, the geochemical package, which is coupled to the flow and transport solver of OpenFOAM. The evolution of the porous media and fluid properties, such as porosity, permeability, reactive surface area, or diffusivity of chemical species, are handled by various models that we implemented in the package. For the present work, PHREEQC was chosen as the geochemical solver. We conducted benchmarks across different scales to validate the accuracy of our simulator. We further looked at the evolution of mineral dissolution/ precipitation in a hybrid system comprising of a fracture and reactive porous medium.