Water Softener

Hi grumpy.
What model of cartridge do you have in you BB housing?
If you have hydrogen sulfur in your water, almost no in the cold water and more in the hot water, you should remove the anode rod, just cut it at the top and replace the plug, but before drain about one cup of hot water from the bottom valve then put 1/4 cup of Javex in the rod hole and let it sit for the night.
Carbon filters are usually used in city chlorinated water, but in well water they can be a growing bacteria paradise.
A bacterial test from a lab would be useful to know if you have bacteria in the water then the good solution can be determined.