I need to look at that a little closer. But my gut feeling is it would be ok for a REAL emergency when you don't have access to any other field method of purification. Replacing one salt with another could also have negative impacts when being dehydrated......
I am in the water industry and I can bottom line it for you guys.
One treatment method will not remove all contaminants. Pretty much every water treatment plant has multiple stages to treat water.
Direct Filtration: Removes solids, and microbes. (Virus still may be present) Color, taste, odor and any dissolved metals/minerals will remain. Think MSR, Katadyn or ceramic filters
Carbon filters: Great for removing Color, Taste, Odor and some dissovled organic contaminants. Think Britta filters
Disinfection: Covers Iodine, bromine and derivatives, Chlorination and derivatives, UV. These methods inactivate "Most" organisms. FYI Chlorination will not kill Naeglaria Fowleri (the brain eating ameoba) Also Giardia and Crypto are pretty resiliant critters and are best nailed by Filtration (because of their size) or UV. UV is good because it goes after Virus as well. UV breaks down the DNA or RNA in the living material rendering it inactive. The kicker is if there are a lot of toxins already generated by the bacteria inactivated, they could still make you sick.
My approach in the field is always multi stepped. I have a MSR filter, and I add a few drops of bleach. I am looking into replacing the bleach with the UV as my secondary treatment.\
I know plenty of people with encysted giardia. I do not plan on becoming one of them.