You should go out and buy full salt bouillon. I buy cubes because it is pre measured. The powder is fine too, just make sure you measure for the sodium intake you need. Each serving has around 1000mg sodium. The 2000 mg sodium plus adding regular salt to your meals should get you to the requisite 5000mg of sodium recommended for NK.
Do not pay attention to the scale it will go up for the first few days. You could start with one serving per day and move up to two.