When is water particularly hard or calcareous?
In order to effectively decalcify the cistern, it makes sense to remove the parts of the flushing mechanism and place them in a vessel with a descaling solution. You can find out how and what you need to disassemble in the toilet cistern under "Toilet flushing runs after". Especially with hard tap water, it is usually not only with limescale deposits. Lime reacts chemically to urine. The harder the rinse water is, the more urine stone is formed. As a result, more and more systems are catching up, collecting neutral rainwater and flushing it to the toilet.