Noun
English Wikipedia has an article on:limescaleWikipedia
limescale (uncountable)
A white, chalky deposit of calcium carbonate found in kettles, washing machines etc., especially in a hard water area.
Mixing together chlorine bleach and strong acids (e.g. limescale remover containing HCl) forms chlorine gas, which is toxic. Source: Internet
It is used to remove limescale from boilers and evaporators. Source: Internet
They are commonly used as descaling agents to remove limescale deposits. Source: Internet
Limescale builds up easily on taps. Source: Internet