I don't know whether this topic has been raised previously on this forum - apologies if it has. I would be most interested to know if anyone has any practical experience with the electrical or magnetic devices that claim to prevent or control scale in water systems. As a chemist, I cannot understand how these devices can possibly work and, indeed, for many years I worked for a company manufacturing chemicals for scale control in industrial systems and we looked into this area in case it might pose a threat to our business but concluded that any perceived improvement in scale control using these devices was just chance or imagination. However, being an open minded chap, I would be very interested to know if anyone has seen definite evidence that they work. Also, I have recently moved into a hard water area and a simple device that would prevent scale without chemical addition would be most welcome.