I've been using this non stop at my house now since I got it. I'm impressed with the amount of crap that's getting filtered out, some of it magnetic and I'm thinking some could be calcite. I plan on drying it out and doing a vinegar test on it to see if I can get some crystal growth. Fun project to do with my son. Well anyways I wanted to add that the I've noticed with our tap water that the filter slows down noticeably before it filters a full liter. I would highly recommend taking the plunger to back wash it regularly. It only takes a few seconds to flush it out and its flowing fast again. I also have it set up on a gravity system using a 2 liter soda bottle with the bottom cut off. Takes about 8 to 10 minutes to filter a liter by gravity and only 3 minutes if using a whole 2 liter bottle and squeezing it. I plan on taking an empty liter bottle or 2 and the 2 liter gravity system I'm using now. I can easily roll a tarp up inside the funnel so it wont take up extra space.