I have really hard water, 220 mg/L CaCO3 if memory serves. The worst is the toilet as lime scale is formed and it's like a rock and very hard to clean. What I wind up doing is draining the toilet every so often and filling it with vinegar, not a fun task.
After some googling I found this but I'm not sure it's on the up and up and was wondering what others thought.
http://www.ecozone.com/products/magnoloo/
http://www.amazon.com/Ecozone-Magnol.../dp/B002HORFJ6
The package says
Clever research people found that when water’s treated magnetically, calcium carbonate won’t stick around creating limescale. Instead, it flows freely right out of the toilet.
Get some magnetic attraction with Magnoloo. It’ll help prevent horrid stains and limescale build-up in your toilet without using chemicals so you can love your loo again.
Magnoloo’s easy to use. Here’s how
1. Drop a Magnoloo descaler into your toilet’s cistern – it’ll sink to the bottom and settle there
2. That’s it - water will circulate through the Magnoloo
If you’re in a very hard water area, try using two Magnoloos.
This pack has
2 descalers
Each Magnoloo descaler may keep your toilet free from limescale build-up for up to five years.