The vikan has a purpose made slot along the middle where there are no bristles.
With the salmon tufts of bristles are ripped out to allow water flow through them.
Two things which may help.
1) You need to rip more bristles out of the salmon to allow better flow.
2) If you are using fan jets and they are spraying off center (not 90 degrees to the face), either twist the jets for a better spray or if it's the jets themselves change to one that sprays correctly, if it's the cleantech ones they are hit and miss to how accurate they spray.