Fluval experience?

Hello, I have a Fluval 404 which is about 4 months old. I've read that
eventually the output becomes less and less and the pipes need
cleaning. A few weeks ago I rinsed my pads from the filter and
reconnected it all up. When it started it spat out a small amount of
'matter' no idea what. I've noticed that there doesn't feel as much
pressure coming from the outlet pipe. I'm very worried about cleaning
the pipes, will wait till hubby is off. Has anybody else had a problem
with this? Are the pipes easy to clean, disconnect, reconnect. Really
love the filter, feel like its doing a great job.

Thanks
Mellie