Think about it: you are fighting invisible bacteria that live in metal tubes. They produce a gas that smells like hell. And you win by pouring swimming pool cleaner or swapping a magic metal rod.
It’s a tiny war in your basement. And you, my friend, are the general. You hold the bleach. You command the filters.
So go ahead. Fix that stink. Your next shower will be a spa day. And when your guests say “Your water smells great!”, you can casually reply, “Oh, I just destroyed a colony of underground fart-makers.”
That is a dinner party story worth telling.