An attempt has been made to measure the rate of movement of the groundwater in the limestone aquifer of the lower south-east of South Australia using an electrical resistivity method of following a salt slug dumped into Caroline Sink Hole. The movement rate appears to be less than 20m per year, but further work is required to help substantiate this finding. Future work of this nature should be done using a cave or bore instead of a sink hole to eliminate most interpretation difficulties.