I did the flush one time. Don’t know if I did it wrong, but I retained SO MUCH WATER. Also, a salt water flush really isn’t designed to help with sodium levels. It’s to flush out the intestines. I’d recommend taking a powdered magnesium supplement if you’re feeling stopped up. Otherwise, maybe get a full panel of blood tests from your doctor. They will check your electrolyte levels. And supplement with small amounts of Himalayan pink salt in your water if you’re deficient.
Most people are far from sodium deficient. Salt is so prevalent in everything these days.
If you’re backed up I would start by increasing your fiber and your water before you start messing around with supplements.