That's probably just tap water run through a carbon filter. It will filter some things out of the water but will leave most of the TDS.
I would ask them at the store what process they are using. Expect to get back a blank stare. Most people have no interest in understanding water filtration.
As someone who works for one of those companies it is not just run through a carbon filter. The water is run through prefilters. carbon filters, UV light and an RO membrane