Groundwater tracers such as sodium chloride (NaCl) and the food color brilliant blue FCF (BBF) had been widely used to evaluate flow dynamics, but the possible discrepancy of transport dynamics between the two tracers through a same medium remains obscure. In order to fill this knowledge gap, we combined laboratory experiments and model analysis for transport of the above tracers. We first conducted three progressive experiments, including (1) transport experiments of NaCl and BBF through saturated sand columns packed with uniform glass beads; (2) transport experiments of the two tracers through silica sand columns as a function of travel distances and flow rates; and (3) a long-term adsorption experiment exploring the adsorption of the two tracers to silica sands. All laboratory results show that NaCl exhibits slower and smaller peaks in tracer breakthrough curves than BBF. Further model analysis using the standard advection-dispersion equation (with a retardation coefficient to account for equilibrium sorption) demonstrates that the NaCl plume has a larger dispersion coefficient than that of BBF. Both the laboratory and a pseudo-kinetic model also reveal that NaCl might be observed more by the medium than BBF. Therefore, although NaCl is well known to be a more conservative tracer than BBF, our laboratory and numerical experiments suggest the opposite. NaCl can be less conservative than BBF through laboratory-scale sand columns, probably due to (1) stronger sorption of NaCl to silica sand, and/or (2) relatively stronger mass exchange between mobile and immobile zones in macroscopically homogeneous porous media.