The invention provides a method for contacting liquid with an ion exchange resin comprising introducing liquid into a process tank containing ion exchange resin at an inlet (2) and removing liquid that has been contacted with resin from the process tank at an outlet, the outlet being located above the inlet (2), the process tank including a resin containment region (7, 9) disposed between the inlet (2) and the outlet to impede the upward flow of the resin as it becomes entrained in the liquid flowing from the inlet to the outlet, and a contactor region for promoting contact between the resin and the liquid located below the containment region (7, 9), said containment region (7, 9) containing an array of settling members through which the liquid and resin upflow and which impede the flow of the resin to a sufficient extent that it is substantially contained within or below the containment region (7, 9). Apparatus for performing this method is also provided.