Abstract: A drop-in, portable, water conditioning assembly for use in a tank containing water is disclosed. The water conditioning assembly includes a refrigeration unit having a compressor assembly, a condenser and at least one depending evaporator coil for insertion into the tank water. A heating element also ends downwardly from a base and a temperature controller is operatively connected to both the refrigeration unit and the heating element for controlling both the heating and cooling of the water. A motor drives a depending shaft which mounts a blade. The blade both aerates and circulates water within the tank.