Now for salt and potassium:
The two electrolytes are meant to be in balance but that balance is supposed to have little to do with what you take in barring medications and other supplements. It is meant to be managed by your angiotensin-renin-aldosterone pathway with cortisol having no significant impact at the mineralcorticoid receptors.
There is an interdependency between sodium and potassium but contrary to popular belief aldosterone reacts to potassium changes FAR more than it does changes in sodium. But remember potassium is meant to be mostly inside of cells while sodium outside cells, a delicate balance that involves proper functioning Na-K+ ATPase pumps.
Having more aldosterone tells cells in the body to lay down more Na-K+ ATPase pumps on the cellular membranes which can be helpful provided there is enough ATP and enough T3 (yes that thyroid T3). Think of aldosterone as telling the cells to lay down more factories, the ATP is the electricity to power those factories, and the T3 is used to make the factories more efficient, all contributing to the shuffle exchange of Na and K+ ions across the boundary.
This is especially key for cells in kidney in the renal tubules. Here the pumps when active pull Na back into the blood and exchange for potassium which is sent out through the lumen and out the body (it is more complicated but that is a fair description for here I hope). So higher aldosterone means more tendency to hold onto Na (and hence more water) and more tendency to flush SERUM potassium. The reason I highlighted "serum" is that the tendency to hold potassium inside of non-kidney cells depends on many factors like the ATPase pump activity, presence of sufficient intracellular Mg+2 ions, taurine, and H+ ion concentrations (i.e. pH of blood). If Na levels get too high and serum osmolality changes too much, the level of anti-diuretic hormone (ADH) will be affected, effecting urination frequency and level of thirst (though other factors affect thirst also).
So the short answer is yes salt intake has effect on potassium AND water in the body BUT not that much if the body is functioning well as it stays in a stable homeostasis regardless of what you ingest (otherwise ancient man would have died off and we would not be here: think of how their intakes of electrolytes varied a lot from day to day).
However, if a person is dysfunctional in terms of their adrenals, or their kidneys, or in terms of the angiotensin-renin-aldosterone pathway, or in their pituitary signaling, or take in excessive amounts of electrolytes, or have low ATP levels and thus poor Na-K+ ATPase, or certain medications, or defective activity of 11 beta HSD1, etc. then taking in a lot of salt may lower serum potassium levels and affect water levels (edema vs dehydration, etc.) now to mention the cardiovascular effects.
Personally I think salt gets a bad rap, but I think people consume through their life much more salt than potassium in a relative sense. Most of our ancient ancestors did not have access to high levels of sodium in foods. That is a luxury. But potassium is in almost all non-processed, non-refined foods. That is probably a bigger reason for the CV impact, and of course people get all flustered when it is almost too late to turn things around and drop their salt intake precipitously which in turn impacts a LOT of other bodily systems ... so yeah as a species modern man is kind of not so bright imho
I think any of us who have tried higher amounts of methylation will agree that potassium is needed the more you ramp up. But I don't yet buy the hypotheses that have been suggested for why ... still it is real and has to be handled appropriately.
If you ask me I think the most common fault for most people with chronic problems that touches on electrolytes is their poorly functioning Na-K+ ATPase pumps. Either a) their aldosterone control is compromised and they don't lay down enough factories, b) their T2 is terrible and their factories work poorly, c) they are low in ATP stores and have less capacity to recycle ATP due to Krebs cycle partial blocks, or oxidative stress, or chronic hypoxia at the cellular level and hence their factories are under-powered or d) they have some issues with some of the other defective potassium / sodium membrane channels that impact transport as well (but that is a big unknown I fear).
At least that is my two cents.
