Pentair GRO-50EN Genuine RO Membrane NSF 58

Pentair GRO-50EN RO Membrane – Stage 3 Replacement

Maintain the heart of your reverse osmosis system with the genuine Pentair GRO-50EN encapsulated RO membrane. Used as stage 3 in the Pentair GRO-2550 four-stage system, it provides the main reverse osmosis treatment after the sediment and carbon prefilters and before the final carbon polishing filter.

The high-recovery design produces RO-treated drinking water with less wastewater than standard RO elements. Its encapsulated format, drain line flow control and permeate check valve make it a replacement for systems designed to use this specific membrane assembly.

Key features

• Stage 3 membrane filtration: The main RO treatment stage in the Pentair GRO-2550.
• Genuine Pentair replacement: GRO-50EN, part number 4004424.
• High-recovery design: Designed to improve water recovery while maintaining comparable rejection performance.
• Encapsulated assembly: Includes drain line flow control and a permeate check valve.
• Rated production: 189 litres per day under rated conditions.
• Nominal rejection: 96%; actual performance depends on feed water and operating conditions.

Membrane specifications

• Model: GRO-50EN
• Part number: 4004424
• Maximum pressure: 125 psi
• pH range: 4–11
• Maximum temperature: 49°C
• Listed free chlorine limit: 0.1 ppm
• Typical replacement interval: 2–3 years, depending on water quality, usage and maintenance.

These are membrane specifications. Always follow your complete RO system's operating limits, which may be lower.

Compatibility

Suitable for the Pentair GRO-2550 and other RO systems that explicitly specify the GRO-50EN membrane assembly. Check the model, part number, connections and flow-control requirements against your system manual before ordering.

This encapsulated membrane is not a universal replacement for every RO system or a loose membrane element for a standard membrane housing.

Replacement and maintenance

Install and flush the membrane according to the manufacturer's instructions. Keep the sediment and carbon prefilters maintained and follow the system's water-quality requirements. Assess replacement timing using your system's service guidance and membrane performance rather than age alone.

Need help confirming compatibility? Contact NZ Pump And Water Filters with your RO system model and existing membrane details.

View the Pentair GRO membrane specification sheet