Product review (5 stars): A good, inexpensive alternative.
As a filter you need to let some of the water cycle through before you consume the water. Yes, the first few quarts of water will have a black discoloration and this is not the first filter I've seen do this. It takes only a gallon or two to filter through to work that out.

I'm not a scientist so I have not been able to test the water but it does taste cleaner than without it. I'd buy again.