I'm running a hydrogen gas system that's below 15 psi. All of my fittings are Push-to-Connect fittings of either 3/16", 1/4", or 5/16" OD from SMC. What sort of tubing can I use with this?

Would everyday hardware store vinyl tubing work fine? Nylon tubing? ATP Vinyl-Flex PVC? I can't find any literature about this on the SMC website.