I suppose it could be. My gravel vacuum hose looks like the same material, but maybe thinner. I just took my "parts" to the hardware store and kept sticking them on the different tubing they had until one of them fit right. It was the vinyl 1/2"OD x 3/8"ID hose, worked like a charm. You just have to make sure it's a decent fit on each end. If it's loose at all, you'll end up sucking air or water from the wrong places.
I wish you could buy just the adapters.