An apparatus for treating slides has a base with a cavity, and a heater is located on a surface of the cavity. A tank, which supports a slide rack with the slides submerged in a slide treatment solution, is placed in the cavity with a tank surface immediately adjacent the heater. A temperature sensor is mounted in the base and is operable to provide a feedback signal representing a temperature of the liquid in the tank. A cover is removably hinged on the base to cover the tank. A control system is connected to the heater and the temperature sensor and has a user input/output that is operable to select a set temperature of the liquid and a cycle time.