I use distilled water where I have already added 1 teaspoon of himalayan Sea Salt to a gallon jar.
Do you soak the seeds for a few hours/overnight first?
When I do the soaking, I add the tiniest amount of Epsom Salt (tiny pinch) plus a quarter a teaspoon of unsulphured blackstrap molasses. I soak for 5-8 hours normally. You can also try a tiny squeeze of lemon juice instead of the epsom salt.
I also have one of the 3 tier sprouting trays - do you rinse through 2-3 times a day?
If you try the above and your sprouts are still bad tasting, then I suggest you change your seed supplier.