Why does the dirty water tank of the Xiaomi Truclean W20 Wet Dry Vacuum easily produce odor after use?

The Xiaomi Truclean W20 Wet Dry Vacuum will recycle dirty water into the dirty water tank during use. If not cleaned in time, the accumulated dirty water will inevitably produce a strange odor. Therefore, it is necessary to clean the dirty water tank with clean water promptly after each use. Can be paired with a cleaning brush. After cleaning, please keep it ventilated and let it dry naturally. At the same time, please regularly clean the filter and the filtering basket inside the dirty water tank to ensure better cleaning results.