Instead of using hoses for projects that require fluid plumbing, I prefer high-pressure tubing. It's a great solution when you need to plumb for water, propane or even air. I've used it for some odder applications too, such as to act as a dry, protected conduit for wires underwater. Many varieties are available, so your best bet is to get a few types and experiment.
Uses: Plumbing for propane, pneumatics, hydraulics, fuel line.