it would take a long time to make CS with the electrodes that far apart. only distilled water will do. to get this method to work, you need a certain amount of TDS, total dissolved solids, to get electricity to flow through the water.
what would be interesting would be to start with distilled water, add the liquid minerals called concentrace, hook it up and see which minerals are found primarily in which side - the negative or positive. someone probably already knows this.