Curious if you can describe the setup you use for dispensing Argon into the bottle from the tank.
It's easy though. Tell them what you're doing, and take their advice.
I cut the 10' hose in half, and promptly lost one of the halves. I set up the cut end so it was inches away from fitting into a bottle on the shelf, for dispensing.
Here's a photo: https://komodokamadoforum.com/topic/8968-funky-old-cow/?tab=...
After the obligatory lecture on medical grade argon versus what I was buying (no difference besides a title), the guy tried seven times to talk me up from a 20# tank (which they don't always have) to a 40# tank (smallest standard size, same price to refill). I kept telling him I wanted to stay married. Then the tank ended up in the "middle shed" with the chamber vacuum sealer. When I went for a refill I reminded him of this hilarious conversation, and upgraded to a 40# tank that's still going strong.
I displace air from primary fermenters using CO2 and have had good success ... I would be open-minded to switching to argon but wonder if there is a reason ...
It is said that CO2 can carbonate your wine. If you haven't experienced this, you're fine. I know no reason to actively prefer CO2 to argon, if one is making a free choice.
1atm of (normal air) displaced by 1atm of CO2 is not going to lead to any carbonation ...
But note that re: safety, if you need an inert gas, CO2 is usually your safest option. Why? Unlike other inert gases, you have a decent chance of detecting CO2 intoxication. For most people, excess CO2 is very unpleasant, giving you a chance (NOT a guarantee!) to recognize the hazard and escape. Meanwhile, if your body is short of oxygen because an inert gas leak has reduced O2 concentrations in the room you are in, there's a very good chance that won't notice and at some point will just pass out suddenly and die. Our bodies just don't have the ability to detect a lack of oxygen directly; we evolved to detect an excess of CO2 instead.
Now, I don't want to fear monger: you can certainly handle nitrogen and argon safely with some care and common sense. I myself used to work with liquid helium in large enough quantities to need an O2 alarm. But all things being equal, I'd use CO2.
(Carbonating to 1 atm does not produce much fizz — it only produces any at all because the CO2 offgasses as the drink warms, but bubbles and the taste of carbonation are different phenomena.)
One of the tricks to CO2 canisters is that CO2 liquefies around 6 atm at room temperature, so a canister of CO2 will maintain that pressure until the liquid CO2 is depleted. Dry ice produces about 1 atm of vapor pressure (obviously) which matches the vapor pressure you get when displacing air.
Carbonation (in the sense of making the wine fizzy) will not happen unless pressure is used to drive the CO2 into the wine. You need a supersaturated CO2 solution to get fizzies.
Important safety difference. You'd still need to be careful, but unless you're lying on the floor...
People with COPD need not apply.
CO2 intoxication is unpleasant for us because the baroreceptors in our arteries can detect when the partial pressure of CO2 is too high. This is the feeling you get when you hold your breath. You have somewhere between four and ten minutes of oxygen supply in your blood, but it becomes unpleasant within the first minute because CO2 is building up instead of being exhaled.
People with COPD always have an abundance of CO2 in the bloodstream because their alveoli don't exchange gases correctly. They likely wouldn't be able to tell the difference.
Just saying. Your argument is sound and generally true, but it's true not for everyone.
Argon is a bit less soluble in wine. But both are used by professionals.
Simply, I put a bottle under the SodaStream nozzle and give a few puffs of CO2 to be confident that it's displaced most of the air.
I do this with normal drinking wine sometimes, but more often things like vermouth that I don't open daily.