Get the "00" sized capsules from the health food store. They hold about a 1/4 tsp of salt per capsule. That way, you can tolerate the salt a little better and it still gets into your system to aid your kidneys - they need it.
Many people have said how much magnesium citrate has helped with the constipation. I know I have a renewed appreciation of that particular form of magnesium.
I have just taken up with the 10oz bottles of it in liquid-drink form. There's also a lot of sodium in them, but I have noticed a reduction of my leg and feet edema that I've been suffering from for quite a while now...IOW...it works.
I take just two or three swallows a few times a day now in between meals and the bottles last 2 or 3 days.