Bought the kit about a year ago that came with the #1 filter, faucet and hose assembly, a friend of mine said I should get the #4 filter because it does a better job of filtering. I ordered the #4 and replaced the #1 filter with the #4 and followed the instructions on the box and let it run about ten minutes. I now have about 7 gallons run through according to the meter. I then test the water from the sink which shows 152ppm from our well. I then tested the water from the filter which showed 167ppm, which is worse then then straight from the sink. I was then reminded the refrigerator has water and a filter so I tested it and got 44pm, Didn't know it had a filter, and my bad, cause I can't say it has ever been changed, but it is putting out the cleanest water. I will run about ten more gallons through this #4 filter, if it doesn't clean up, I'm going to look for a refund, and a different brand.