In article , Bubba wrote:

The more you drain, the more you refill. Unless you are refilling with
clean distilled mineral free water (you arent) you are introducing
added minerals each time. Its a balancing act. You have to add water
once in a great while but the more you add the more minerals you add.
Expansion tanks do NOT need to be drained twice a year. If you have to
you need to find out why. Anytime you drain water at the boiler, you
usually wind up with air in the system at the upper radiators. Then
you have cold radiators.

I'd be more concerned with adding oxygen rich water to the system
than minerals. Hot, oxygen rich water is quite corrosive and will
eat your boiler. Or does the air stripper take care of that because
hot water can hold less disolved oxygen than cold water?