A method of operating an electrochemical separation device comprising a dilution compartment, a concentration compartment, an ion exchange membrane positioned between the dilution compartment and the concentration compartment, first and second electrodes (200, 220), a first feed stream fluidly connected to the dilution compartment, a second feed stream fluidly connected to the concentration compartment, and a concentration compartment recycle stream the method comprising: directing the first feed stream to the dilution compartment to produce a product stream; delivering the second feed stream to the concentration compartment to produce a reject stream; recycling the reject stream having a first concentration of ions to the concentration compartment via a recycle line fluidly connected to the reject outlet and the inlet of the concentration compartment; blending the reject stream with the second feed stream in the at least one blending tank positioned within the recycle line and within the recycle stream to produce a reject and second feed blend; wherein a valve is positioned on the recycle line upstream from the blending tank and is configured to selectively discharge the concentrate reject from the device or to deliver the concentrate reject to the blending tank; periodically discharging a predetermined volume of the reject stream in a timed batch cycle to prevent precipitation or scaling in the concentration compartment, wherein said predetermined volume is between 50 % and 100 % of the liquid volume in the blending tank; wherein a control module in electrical communication with the valve is configured to replace the discharged volume of reject stream with an essentially equivalent volume of the second feed stream having a second concentration of ions lower than the first concentration of ions; measuring ionic concentration of the concentrate reject by a sensor fluidly connected to the reject outlet; wherein the control module is electrically connected to the sensor and configured to discharge the volume of the concentrate reject in response to the measurement of the ionic concentration of the concentrate reject received from the sensor, when the ionic concentration in TDS of the concentrate reject is greater than 12 000 ppm, preferably 12 200 ppm. directing the first feed stream to the dilution compartment to produce a product stream; delivering the second feed stream to the concentration compartment to produce a reject stream; recycling the reject stream having a first concentration of ions to the concentration compartment via a recycle line fluidly connected to the reject outlet and the inlet of the concentration compartment; blending the reject stream with the second feed stream in the at least one blending tank positioned within the recycle line and within the recycle stream to produce a reject and second feed blend; wherein a valve is positioned on the recycle line upstream from the blending tank and is configured to selectively discharge the concentrate reject from the device or to deliver the concentrate reject to the blending tank; periodically discharging a predetermined volume of the reject stream in a timed batch cycle to prevent precipitation or scaling in the concentration compartment, wherein said predetermined volume is between 50 % and 100 % of the liquid volume in the blending tank; wherein a control module in electrical communication with the valve is configured to replace the discharged volume of reject stream with an essentially equivalent volume of the second feed stream having a second concentration of ions lower than the first concentration of ions; measuring ionic concentration of the concentrate reject by a sensor fluidly connected to the reject outlet; wherein the control module is electrically connected to the sensor and configured to discharge the volume of the concentrate reject in response to the measurement of the ionic concentration of the concentrate reject received from the sensor, when the ionic concentration in TDS of the concentrate reject is greater than 12 000 ppm, preferably 12 200 ppm.