Have a look down the end of the dump valve and if its twin piston u will see a thin metal piston inside a larger black plastic piston.

Any piping is ok, but we all know silicon vacuum hose looks the nuts The norm is about £10 for 3 metres, and small cable ties are the best way of securing the pipe onto conncetions (and if u really want to be a tart u can buy some matching coloured ones )