I have had excellent results with the hiker pro as well. And thanks WV for the tip on alum and swim pool coagulant. That is a great idea. I have filtered some pretty nasty stuff down in the canyons. Water so bad, we had to push the leeches and gordian worms out of the way to get to the green water. Like WV said, coffee filters are a part of the system, covering the inlet tube.
Actually, my hiker pro is not even original anymore. While furiously pumping water in a downpour in the Weminuche, I broke the handle off the pump. I called katadyn tio see if I could buy a replacement. They said "no you can't buy a new one. We are sending you a new one free." Last year, after many years of faithful service, a little pinhole leak developed in a seam. Again, a new housing, free of charge was in the mail as soon as I called. I'm sure they will continue to send replacement parts as long as I continue to buy those expensive filters. However, I usually get two seasons out of a filter by backflushing and drying between each trip.
Beware the squeeze bottles. Nearly every one I have seen will have a slight leak around the threads when squeezing the bottle. And that puts untreated water right in with the clean.
There are straws and tubes that filter but remember, the smaller the filter the less overall capacity. There are also many ways to treat the water to kill all pathogens. WV mention chlorinating tablets. Also, products like aqua mira. These work well except some means of filtering solids must also be used. The same for steripens. They use UV to kill all pathogens, however, they are electronic and have been known to fail.
For really cheap, a one liter clear plastic empty pop bottle, with a recycle code of 1, left in the sun for at least six hours will also kill all pathogens via ultra violet rays. Kind of a slow way to git r done but something to remember in an emergency.