slow drain hose collapsed

having issues with a slow drain on the washer, it seems to be collapsing the tub to pump hose. I have tried cleaning the drain, the pump appears to be working fine as it has enough suction to collapse the tub to pump hose completely any idea on how to fix this?

Since the drain is OK and the drain filter clean, it could be that the drain is plugged on the tub side.
I am assuming that it is installed as recommended by the manufacturer re: there is not an air lock at the house plumbing end.

Here is a manual which you may find useful.
http://appliancejunk.com/forums/index.php?action=downloads;sa=view;down=468
You will have to join the site and be logged in to be able to download it.