Use soluble paper in the fu, should never block again. Also think about moving, no pun intended, to organic fluid. Elsan organic goes in top and bottom tanks and dissolves material so should prevent blocking. Soluble paper and organic both quite a lot more expensive than normal stuff but.......
That's true Rob, but the thread wasn't all waste matter.Sadly we now discover that our answers given in good faith and in the true spirit of the forum were not at all of interest to the original posting - perhaps plumbing the depths would be an appropriate description.