After listening to at least 100 of these over the years, I’m really not sure how this podcast was released in the form it was as it was kind of a mess.
A great (common) question from a listener on how to get extra sodium into their drink without making it too “salty.” Started off with good potential explaining that you have to account for the fact that NaCl is only partially Na by weight - although then that ambled way more than necessary given the expert guest should known this kind of detail off the top of their head - and then it just started going off the rails talking about using NaCl to a point and then supplementing with separate electrolyte tablets, no updated guidance on how to quantitatively do that and I’d summarize as “oh you just have to try lots of things…” - but finally well into this discussion, sodium citrate is mentioned, and the host and guest admit they know nothing about it other than the fact that it’s in pretty much every major sports drink. 
At this point, probably would have been good to just drop the question from the episode, go research it, and bring it back for a future podcast. But the bad speculation continued with neither of them knowing anything about what they were talking about.
There was a discussion how how expensive it is vs. salt and would add 5x the cost. Go on Amazon - it’s literally $0.02/gram. It is not even remotely relevant to the cost of making a homemade drink. The cost is all in the maltodextrin and fructose that make up the vast majority of the mix by mass - and they are also dirt cheap compared to commercial mixes.
They speculated about the taste - it’s very well known and easy to get a bag and see for yourself - slightly citrusy but mild compared to citric acid (also useful for flavoring your drink) . This again is a reason why it is so widely utilized.
And fundamentally, it’s used all over the place for good reason - it’s a way to get more sodium in without the Cl that causes various internal distress - exactly what the listener wanted to accomplish.
Just really disappointing episode that did nothing useful to answer the question when in fact, there is a very clear, simple, economical solution - use salt as you prefer for taste, and make up the balance of Na via sodium citrate (accounting for the fractional weight that is actually Na) to reach your desired Na level.
This should be re-done sharing an analysis of the options with quantitative cost info, pros/cons of typical additives people use for both Na and flavors and malto:fructose ratios, talk about options if someone wants to add other trace minerals, and share a spreadsheet that people could use and tune.