Take it to Home Depot, Lowes, ACE, etc so you can match the size.
But replacement length of bulk hose off reel, or buy same ID/Od Tygon clear tubing in whatever length you need.
Buy two 1" concentric slip couplers in pvc/plastic, copper/brass or stainless (think they are 3/8" OD)
Slip the couplers into the ends of the existing hose end the jumper & seal/tape joints if needed (may not be nessisary to seal with the internal couplers, since you should only be working about 40 PSI pressure).
I replaced mine with one from Lowes. It's a residential style one with massage head and longer hose. I havea seasonal trailer...so shutting of the flow on the hose isn't an issue. (I have no gray or black tanks) You can see pics in my gallery.