Yeah, you're right; I probably don't want a jacuzzi. We almost bought a house with one about ten years ago and we likely would have never used the thing.
I've almost always had well water and it's been a love/hate thing. My parents' house has extremely hard water, an incredible amount of iron and other minerals in it that they have never been able to reconcile. They can't have a dishwasher and have to change their faucets out frequently because of the buildup. Our white clothes were always orange, growing up. In fact, to this day I still avoid buying white clothes and towels and sheets and stuff just because of the way I was raised with hard water. They don't have space in the boiler room (it's an old school house) for a decent softener and iron removal system apparently.
At our last house, the well water was alright and we did change out the tank once. It was a very deep pvc well that I was thankful for on account of the heavily sprayed potato field we were neighbors with. Now though, I'm nervous about this one being just yards from the heavy liquid manure application that's going on and not knowing how deep it is. I've been told to keep an eye on the surface water and believe me, I WILL. As soon as we get a thaw, I'm testing the well.
But yeah, I agree with the logic about the slime. I know this tank is old and they're fairly inexpensive to replace so maybe that's something to look into.