Magnetic frustration is the phenomenon of being unable to satisfy all magnetic interactions present in a system. It draws a lot of attention as it is the source of exotic behavior in many magnetic materials. Although it has been thoroughly studied in various groups of compounds, little progress has been made in its examination in the half-garnet lattice family, particularly terbium gallium garnet(TGG/Tb3Ga5O12). TGG is a promising candidate for hosting a magnetically frustrated spin liquid regime, but its existence in TGG has never been confirmed. Defining a crystal field scheme is a crucial, initial step in the investigation of any rare earth based magnet, and inelastic neutron scattering is the most reliable method of doing this. We propose a combined study at the LET and MARI instruments to observe, for the first time, the full crystal field spectrum of the Tb3+ ions in TGG.