Does anyone know what fittings/adapters will allow an Omnipure CL10RO carbon filter (often listed as a post-filter option for the GE PVRN18Z RO system) to adapted to the GE PVRN18Z? The OEM filter has male threaded connections (unknown spec) while the the Omnipure after-market filter has (apparently) 1/4 inch NPT female ports. Is there an "adapter kit" available? Any help would be appreciated.