Most people use the Epsom Salts (=magnesium sulfate). The SWF (Salt-Water-Flush) is with Seasalt 2 tsp in a quart of water if I remember right, it should taste like salty chicken broth and you should drink it all.
You sometimes have to play with the right amount, you want it to run through you so the body does not absorb the salt.

Are you sure you're not confusing SWF (Salt-Water-Flush) with Epsons?

If you've never done SWFS before, it's not really a good idea to do your first one after a Liver-Flush because like Hanna said, you can absorb it all if the amount is slightly off. On top of Liver-Flush symptoms/hangovers, you really don't want to be bloated with 32oz of water and all that salt just sitting there.

Click on SWF (Salt-Water-Flush) . It'll tell you what it is. 32oz of water with 2teaspoons of 100% Sea Salt . You have to down it as fast as possible. I get my 32oz down in under a minute..but I'm used to it from doing the MC.