The only good thing about these best, alkaline water sources is their taste and purity.

There is nothing special about alkaline.

I would suggest that you ditch this alkaline idea.

Get these scientists you're going to work with to research water taste. Good tasting water can wasily fit the hype of "good water". Maybe the smell (chlorine smells is bad), maybe the colour (very slight bluish tinge may infer a "clean" image.) Shit like that. It doesn't have to be actual changes to water. Maybe some light tricks to the container of the water could manifest such illusion without actually do anything to the water that has a potential of some lawsuits.

For purity, just devise some generic filtration system and youre good to go. Or just make a reverse osmosis machine, then have the machine do something about the taste later.

The rest, do whatever marketing gimmicks you want.

But, if youre looking to make something revolutionary, something that could cure cancer (or ambitious shit like that), out of plain water, youre out of luck.