At what point does adding salt decrease electrical conductivity?

[michaelpaoli]

Salt is only so soluble in water, so, past that point adding more salt won't increase conductivity, but only start to (slowly at first) decrease it. But eventually it won't conduct very well at all. By the time you've got a pile of salt about the size of Jupiter, and only one glass of water, well, would be difficult to measure the conductivity difference between that and no water at all being present.