forming a series with a first series cell being in a first position of the series and receiving the source fluid a last series cell being in a last position of the series outputting product fluid and intermediate series cells the fluid transport network and controller are configured such that the controller operates the valves so that at said first time fluid may be directed in a reverse direction through a connected second cell whereby simultaneous multi stage purification and cell regeneration may be achieved the fluid transport network and controller are configured to operate the valves to rearrange the connected first cells and the second cell by replacing the last series cell with the second cell and replacing the second cell with the first series cell the fluid transport network and controller are configured such that the controller operates the valves so that at said second time fluid may be directed in a reverse direction through second cell which was the first series cell at the first time the rearrangement of cells in the series may be accomplished without disconnecting any of the cells from any of the respective cell connectors in the embodiment of the last paragraph the controller may be configured to apply a reverse a voltage of the second cell and apply a forward voltage to the first cells the fluid may be water the fluid transport network may have water channels and the network is configured to connect to water and water purification cells the connectors may be adapted for receiving electronic deionization cells in a variation the first cells at the first time may be at least three in number having the first series cell the last series cell and intermediate cells ordered by rank in the series and the intermediate cells at.