we had a new water heater put in a couple years ago,
and soon after we had that smell. my softener guy, and
my plumber said that since i had the softener, the anode
could be safely removed. i think it was magnesium. i pulled the
water input out, cut off the rod that was attached to it,
and put that fitting right back into the tank saving the need for any additional parts.
smell went away.
as far as using potassium, i was told by my softener guy
that it's ok, unless there was iron, how much
he wasn't sure, but felt there could be issues caused by
the iron/potassium mix.
i am considering some filters also, as s/o has concerns from
the sodium content of the water. with my hardness of 25, the
formula worked out to 187 grams sodium per quart. if you look
at any food in your fridge, (2-300 grams per tablespoon of many items)
this is quite a moot point. but, i am still being asked to look into
alternatives. I will test my non softened spigot at the sink and see
what they might recommend for a filter, either undersink or whole house.