Iíve had problems w/ Hiker Pro filters and I will probably have problems with the MSR Hyper Flow filters (I would love to be proved wrong).
Hiker Pro claims 0.3 micron filtering.
AutoFlow and HyperFlow claim 0.2 micron filtering.
Yet the filter I use only claims 0.4 micron filtering (First Need). Thus you would expect the First Need to filter less impurities than the Hiker Pro. However, Put 2-4 drops of dark food coloring in 1qt of water. Filter; then see if the filtered water comes out clear. If this test works, then this is also a good method to see if one has accidentally cracked said filter. Hiker Pro always lets the colored water come right through. First Need does not.
Will someone prove me wrong on the MSR Flow filters?
I got this from our water specialist at Cascade Designs. She said, "The threads on trying to test the filterís ability to remove food coloring from water is not an appropriate test. The filter removes particulate and pathogens down to 0.2 micron, not dissolved solids such as salt, food coloring, acids, etc. If you filter a coke, for instance, it will still be the same brown color as it went in, but all of the pathogens bigger than 0.2 microns will be removed."
My understanding is that the First Needs Filter element is basically a positively charged Carbon Matrix (I've cut into one and it looks like a big chunk of black volcanic rock). This would explain it's ability to remove the food coloring where other filters won't. The Miniworks EX does a better job than most, but that's because of it's carbon core. The HyperFlow won't take out any of the food coloring because it has no carbon component.