| Purtrex 75 micron filters are nominally rated to filter sediment down to 75 microns. The smaller the micron rating of the Purtrex filter, the smaller the size particle the Purtrex water filter cartridge will remove. For comparison purposes, the human hair has a diameter of approximately 70 microns, and particles smaller than 40 microns are not visible to the human eye. The Purtrex 75 micron filters are good to use for first stage sediment filtration to reduce larger sediment particles out of the water. Then, it is good to use a second stage sediment filter rated to a smaller micron rating to reduce smaller sediment particles out of the water. |