I recently installed a mixer shower but realise now the hot water pressure is non-existent (the tank is pretty much at the same height as the shower head. Its gravity fed and the cold water feeder is right above the hot. I cant get a direct line from the tank to the mixer to install a dedicated pump. Question is, can I use a pump on the outlet for the whole of the house hot water system ie attach a pump to the current (and only) outlet from the tank?