I just bought a Katadyn Hiker Pro, took it home and put tap water through it. According to the directions you should put a liter through it to clear out 'harmless carbon' that in my case came out a fizzy blue. I was putting filtered tap water through, just to be thorough, but then I tried straight tap water to compare results with the Zero Water filter I've been using on my tap water. Tap water at my digs comes in at 395 parts per million (ppm) dissolved solids. Through the Zero Water filter the output is 12 ppm, which, considering it's name is 'Zero' you'd kind'a expect better. I put the tap water through the Katadyn, and the ppm is 395, as in no dissolved solids filtered out. The Zero Water does not claim to filter out Giardia or any of the other nasties out there, and it seems that if the Katadyn filter can filter out something as small as cysts and protozoa it would also filter out dissolved solids. So if someone could enlighten and reassure me that my Katadyn is not defective, I would greatly appreciate it.
no clue here. you say you are able to analyze the ppm of your water at home?! That's pretty amazing, wish I could...but then I probably don't really want know what my local water company leaves in the water...I've always wondered what chemicals and crap are in my local water. ugh.
"Disolved solids" are at the molecular level and far smaller than anything a typical passive filter can remove. The active carbon element will remove some of the more reactive ones which will bond to the carbon thus removing some tastes and smells. This bonding eventually stops the carbon from working and is why the filter cartiges wirh carbon elements in like the Hiker have to be replaced every so often. Otherwise, filters like the Hiker Pro just mechanically prevent particles larger than around 0.1 - 0.2 microns which will remove cysts, protazoa, most bacteria and some of the larger virus. Grit, silt and micro plastic is also removed but tend to clog up tbe filter which is why filters like the Sawyer Squeeze have some advantage. Note: The Squeeze does not have a carbon element.