Cheap 25mm marine sanitation hose (sometimes marked odour free) retails for around $12 – $15 only lasts 12 to 18 months before it will permeate. A rubber approved sanitation hose that costs around $55 – $65 per metre will last 10 years.
Hard Piping (must be high pressure PVC water pipe CLASS 18) will last the life of the boat and will never permeate.
Professionals use hard pipe and amateurs use hose.
25mm hard pipe costs around $15 – $18 per metre so is a good alternative to hoses.
You will need to put hose at each end but the bulk of the piping should be hard pipe.