Filter for Use in Hemodialysis Water and Concentrate Devices. The ENX Endotoxin Ultrafilter assists in preparing water or bicarbonate concentrate to meet the requirements for the production of ultrapure dialysate according to the ANSI/AAMI 11663 standard. The filter’s unique proprietary single-stage design removes bacteria, viruses, endotoxins and other contaminants greater than 0.005 micron (5 nanometers), and has an expected life of up to 6 months.