I had a friend state that all his roasts out his Behmor 1600 "tasted burnt" -- even after using my methods.
What actually happened is that he was using boiling water in his Aeropress/Disk Fine (his preferred method which I certainly do like too). I told him to boil, and then wait 60-90s before putting the water in. That's usually enough time to cool off a kettle or a measuring cup from the microwave off 10-15*F or so.
Now he claims it doesn't taste burnt. It was the water extraction. I agree that the sweet spot is 190-205 *F or so. I am really digging letting my coffee "steep" in the Clever now though, so I'm still thinking an automatic machine is out. But Setting a precise temp on an electric kettle will happen eventually. My wife shot me down on that since she thinks the tea kettle on the stove is perfectly fine.. but one day, the electric unit will magically show up.
Sorry to hear about the hardness issue and your unit. I am very careful now with any purchase like that... I also decided that practically I can not afford bottled water for things like that either.. so I suppose, for now, the manual methods will do...