We built our new house 7 years ago. I'm wondering if there is something I should be doing with my water softener to clean it, or revive it, or whatever. I went way too long on my last in-line filter change. When I changed the filter recently, the old one was in a pile at the bottom of the holder. There was a black residue on the inside of the holder, and the smell wasn't so pleasant. Is there a chemical that I add to the brine tank to clean it up? And what about cleaning the resin beads inside the softener?