Dirt in Ultraflow water pump pipe

I've found a lot of dirt inside the clear plastic water-pipe in my Truma Ultraflow Pump Assembly. It is black, maybe carbon or maybe bacterial. Has anyone fond similar? Also, I want to replace the clear plastic pipe but can not figure out how to open the bespoke 'jubilee clips' that Truma use to clamp the piping to the pump assembly. They do not respond to the gentle approach, i.e. pliers and a screwdriver. Does anyone know if they are designed NOT to be opened, i.e. a single-use closure that has to be destroyed to remove it.   Many thanks for any advice.