If anyone could advise it would be much appreciated. I am in the process of renovating the bathroom and will be removing, temporarily, the indirect hot water cylinder. I have yet to look inside, via the immersion heater aperture, but I am assuming that there will be quite a bit of "furring" inside. As in the case of an electric kettle wherebye fluids are available for de-furring, is there a chemical available which can be used for a hot water cylinder? I am not in a particularly "hard " water area but, as the cylinder is now a few years old, I expect to see a fair amount of deposit on the primary heating coil. Any advice would be more than helpful.