Two tricks about salt and coffee:

1) This one I learned from an old truck driver who probably had more miles in reverse than these "truck driver training school graduates" have going forward. We ran the NYS Thruway together for a few years. Stop in a service plaza at 2:00 am and the coffee has been sitting on the burner for a few (probably more than a few) hours. Talk about strong and bitter! He would open one of those little salt packets available in fast food places and dump it in his cup. Takes the bitter right out of it.

2) I buy the cheapest coffee I can find for home/office use. Usually Clover Valley from Dollar General. When I put the grounds in the coffee maker I sprinkle just enough salt on top of the grounds to look like a light dusting of snow. Then brew as normal. No bitter taste. The ladies in the Ladies Bible Class that I make coffee for are always bragging on how good my coffee is. Of course, one of those ladies spent several years in Cajun country and likes her coffee strong enough to walk on its own. I'm sure that too much salt would have the opposite effect.