You will deplete sodium way
You will deplete sodium way ahead of potassium and sodium depletion is life-threatening in a much more immediate way so, in my view, it is correct to be more concerned about it.
Last year on long runs in the heat I would carry coconut water in my Nathan bottle and a baggy of sea salt in the pouch. At mile 8 in 90+ degree heat, I would drink a fountain Coke (better than the the particular artificial dyes in Powerade/Gatorade for me, personally - wouldn't drink Coke this year, though, unless I was desperate). Then I'd mainline sea salt - that got stares. I'd fill up my Nathan with plain water and run another 6. AngieB is a Nuun electrolye replacement rep and she mailed me some tablets that fizz in water. I had forgotten why I couldn't have them - the flavors are from "natural flavors" which means chemical flavors which give me an instant migraine. But if "natural flavors" don't normally bother you in other foods, they might be an option (no sugar or colors added). Another option is sweet stuff (honey, maple syrup, etc) mixed with lime and sea salt. Recharge which is a heath food store variety of Gatorade is also popular.
I threw up throughout my pregnancies, including alot of electrolyte replacement drinks I was taking because I was so dehydrated and unable to keep anything down, so I am kind of off alot of them for good for that reason in addition to my wish to adhere to a low-crap diet. There are alot of options, it's a matter of getting the right mix for you. Some have no carbs, like Ulta (not sure about the name - has stevia instead), or no sodium, so you need to watch out for getting what you really need individually for your body.