Bought this house with an unmarked water softener system. I’ve been able to determine it’s a 32k twin tank system with a Fleck 9000 or 9100. Not sure what the difference is though. All mechanical. Bypass valve and metal parts appear to be brass. I do have the service manual but don’t know the settings, flow rate, injector size, etc.. The only date I can find on it says the timer mechanism was assembled in 2003. I’m having a problem where during the rapid rinse cycle water is coming into the brine tank thus causing the brine tank to overfill. I’m thinking about replacing the brine valve assembly and see if that fixes the problem but I hate the thought of going through this thing replacing one part at a time. It looks like the whole thing could stand to either be rebuilt or replaced. Are these things worth rebuilding or am I better off replacing it? If I replace it any recommendations on Fleck 9000/9100 mechanical or SXT? Thanks!