ProOne Water Filter Systems Frequently Asked Questions Mar 30, 2018 Written by Carol Trimmer Filed under Alexapure, Berkey, How to store ProOne filters, Nomad, ProOne FAQs, ProOne filter is leaking, ProOne Filters, ProOne Shower Filters, Propur Filters, Propur Traveler, Shower filter removes Arsenic ProOne Water Filter Systems Frequently Asked Questions Got a question about a ProOne (formerly Propur) water filter system? Check out our FAQs that highlight the ProOne company background, ProOne product lab test reports, important information about contaminant reduction, and filter life estimates.Â