Venturi Failed On A Hydor Crystal Duo

[paulcdr]

hi

i have a hydor CRYSTAL DUO internal filter. the venturi device on the top has stopped working. i have taken it apart and cleaned it but to no avail. anybody got any clues to what has gone wrong?

thanks

 

[Dorkhedeos]

i dont have one of these filters, but im pretty sure a venturi cannot fail as it is just a constriction in a tube to help increase the speed and reduce the pressure within that constriction. post a picture?