Hi Clare (FYI)
This photo was taken about 6 hours after connecting the charger leads to the electrodes 2 days ago.
This is our Waitara tap water after passing through a 0.5 micron charcoal filter. Both compartments were filled with the same water and what you see in the left tank is what came out of the right (and of course what was in the left tank).
The residue has to be removed with a nylon brush and citrus detergent. After seeing this I am not planning to drink any more untreated tap water, (ever).
Note: Unfiltered tap water produces the same dark colour (not charcoal from the filter), whereas unfiltered natural spring water produces a whitish brown colour.
This 1minute video is well worth the look. Rod