I have seen those blocks of something that go either in the cistern or hang under the rim. I was never quite sure if they were for aroma, disinfecting, or if they did something to control limescale.

I don’t suppose they would all be created equal. Guess I need to look into it.

That was one of my questions. I am looking for min effort. If a quick brushing simply prevents the limescale, that would be less time and effort. But if limescale would still build up anyway, then I would not be interested as it would just add to the big effort every few yrs.