The pump can work even well below 1Hz (if necessary) but not every Bartels driver does support it.
The mp-Labtronix controller has a frequency range of 1-300 Hz. The mp-Highdriver4 and the mp-Highdriver have a lower frequency limit of 50 Hz. This cannot be disabled or changed. The mp-Lowdriver has a typical frequency range of 8-2000 Hz, but these Bartels electronic can work at 1 Hz as well, but each electronic just can control one micropump.