We have a primatic cylinder (see below!!!!) and have been told that we cannot have a shower that needs a pump, as this could affect the water bubble inside the cylinder. I assume this means a power shower, that runs off the cylinder hot water. Does anyone know if it would be okay to have an electric shower, with a pump, that runs off the direct mains. Can you get them, or are we restricted to a normal electric shower, off the mains. Any comments would be gratefully received.