A blood treatment apparatus is disclosed. The example apparatus includes a blood treatment unit including a fluid inlet and a fluid outlet and a blood line. The apparatus also includes a fluid line including an upstream fluid line configured to receive electrically conductive treatment fluid from a fluid source and pass the electrically conductive treatment fluid to the fluid inlet of the blood treatment unit and a downstream fluid line connected to the fluid outlet of the blood treatment unit for delivering the used electrically conductive treatment fluid to a fluid sink. The apparatus further includes a flow divider arranged in the downstream fluid line and configured to separate the used electrically conductive treatment fluid in the downstream fluid line into to a first fluid section and a second fluid section, thereby electrically isolating the first and second fluid sections.