Pilot Testing Ion Exchange Resin (IEX) can go from very simple beaker testing to complicated column testing. Space velocities regenerate quantities, loading capacities, ion leakage all terms that get accumulated together to prove or disprove a resin(s) ability to load a single or set of specific ions. Not getting all the resin’s operating parameters correct will disqualify the results. Laboratory test for capacity, moisture content, bead size, metals fouling, etc. – What does it all mean? At last count, there were over twenty-five separate ion exchange resin tests (analyses) that were available to end users. Standard testing procedures identify the resin properties but more specific procedures can be used to identify problems with equipment operation. Then, there is the cost to consider; simple cation resin testing (moisture content, total capacity and bead integrity) is in the $200/sample range. However, add to this Chatillon, HIAC particle size, metals and % regeneration test procedures and the lab work can increase to over $1000/sample. In this paper, the author will explain the “must-do” pilot and test procedure and why they are important and the key to understanding how resin does ion exchange.