Answer
The pump tubings used by the peristaltic pump are consumable material with a limited lifetime and should be exchanged at regular intervals (approx. every 2 months under continuous use).
Different positions can be used, the position should be changed monthly.
The pressure of the pump tubing cartridge should not be too high: increase the pressure step by step until you observe a flow; add then 2 more steps.
Use 3-stopper long-life tubings: 6.1826.3X0.
Inline filters have to be used and exchanged quarterly or if the backpressure is too high.