A device for monitoring a milk tank (3). The device is provided with a monitoring-unit (11) comprising a computer (12) and a memory (13) for storing data at least temporarily, a thermometer (14) for measuring the temperature of a fluid, such as a liquid, present in the milk tank, and for supplying to the monitoring-unit a temperature signal that is indicative of the measured temperature, and with a meter (15) for measuring an electrical parameter, such as the conductivity, of the fluid present in the milk tank and for supplying to the monitoring-unit a parameter signal that is indicative of the measured electrical parameter. An assembly of a milking robot with an automatic starting-up-unit and such a device.
