As shown in FIGS. 1 and 2, a baffle 14 in the form of a section of flexible baffle made of rubber or a PVC material or other flexible material divides the interior of the tank into two separate flow channels so that liquid entering the inlet 13 flows over a bank of ice encapsulating units in the bottom section of the tank and then flows back toward the outlet 12 over a bank of ice encapsulating un