There is no formal scheme in the field of cave and Karst hydro-chemistry to allow workers to demonstrate the quality of their analytical work. Alternative procedures which allow them to do so (by calculating ion balances, or by comparing observed conductivity with the theoretical conductivity) both require the determination of ions which may be of no direct interest. Ion balance data from recent studies at sites on Mendip are presented. Ion balances provide a clear measure of analytical quality, and in many cases comparisons between imbalances and inter-ion regression data located analytical mistakes. Ion balance data are precise and easy to interpret, giving the method a significant advantage over conductivity-based procedures. Rigorous procedures in the use of primary standard solutions led to the detection and correction of an important source of systematic error.