For me personally, two level teaspoons of salt ALWAYS get absorbed straight into my system (I'm on my third MC). I have to use 2 1/2 - 3 tsps of salt per quart of water to get it to work. Totally gross, but worth it!
Also, I've found that the SWF (Salt-Water-Flush) is most effective for me if I drink all of the salt water, then after about 20-30 minutes, drink about half a quart or more of water. THAT always gets things moving pretty quickly.