i checked hobby lobby for silicone tubing but they didnt have it. unless the worker that helped me was incompetent. which is possible because the store was just built.
Not silicone, but check your Ace Hardware if you got one nearby. Mine sells all sorts of clear & white tubing by the foot in a variety of sizes. Haven't looked yet to see if any of what they sell is small enough, but it will be worth a look. Considering it's sold for some uses such as water lines for ice makers it should be good.