GE PNRV12ZBL01 Reverse Osmosis System Compatible Replacement Water Filters, RO Membranes, Water Tanks, Faucets, Water Testing and all of the Parts to Keep Your GE PNRV12ZBL01 Water Filter System Operating Properly. The carbon pre filter and post filter should be changed at least every 12 moths. If there is high sediment levels in the feed water the pre filter will need to be changed every 6 months. This GE 3 Stage RO system uses the GE FX12P filter as the per filter and the post filter. Order 2 of the carbon blocks below for an annual filter change. The GE FX12M Reverse Osmosis RO Membrane should be tested using a TDS meter and replaced after efficiency drops.