I've tried two different ones from amazon. Both have a bad taste and smell.

https://smile.amazon.com/gp/product/B086XH2FTK/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

https://smile.amazon.com/gp/product/B07MKN2HP4/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

Also interested in one that works.

I just sat down to research this exact same issue that I’m having. I got this hose from amazon. I got a 20lb tank from Roberts Oxygen Company. 

The soda has a distinctly bad taste and odor, hard to describe exactly what. I experimented by disconnecting the sodastream from the hose and expelling a good burst of gas, then reconnected and made a bottle of water immediately. There didn’t seem to be any noticeable bad odor or taste. But after making another bottle 2 hours later the bad taste/odor was back. I do not see anything on my invoice that indicates food grade co2, so maybe that’s the issue. Will try clearing the line after each use to see if that helps.