Pump assembly having an impeller, a motor, and a shaft, with the shaft passing from the motor to the impeller through a fluid reservoir and a seal arrangemnet with a tration

A method for detecting a concentration change in a fluid reservoir in a seal arrangement in a pump assembly comprising an electrical drive motor, the seal arrangement with the fluid reservoir, a shaft, at least one impeller connected to the drive motor via the shaft, wherein the shaft extends between the drive motor and the impeller, through the seal arrangement with the fluid reservoir, the method comprising the steps of:

• providing a concentration sensor, for detecting a fluid concentration change in the fluid reservoir, arranged in operative communication with the fluid reservoir;
• providing a second sensor, for detecting a further parameter of the fluid reservoir, arranged in operative communication with the fluid reservoir;
• connecting an evaluation device to each of the concentration sensor and the second sensor, wherein the evaluation device being configured to carry out an evaluation of at least one reading of the concentration sensor taking into account at least one reading by the second sensor;
• and
• evaluating, with the evaluation device, a reading of the concentration sensor in dependence on a reading of the second sensor.