Soda dispensor

I am looking to add a soda (Seltzer only) to my kitchen. Looking for some ideas and parts. All I want to do if take the cold line and mix it with a small gas canister under counter and dispense it near the sink. Anyone try this and if so where do you suggest to purchase parts?

The CO2 in carbonated water reacts with copper and copper alloys (EG brass) so you must isolate it from your cold water system with an approved SS backflow device and use plastic and SS after that point, using a valve meant for carbonated water, or you will ended up with the worst tasting soda you ever encountered. Probably not too healthy to drink either.

The CO2 cannister is a high pressure device, therefore you need an APPROVED back pressure/backflow preventer in the water line to it, and it usually has to be stainless steel, (read "big bucks").