Franklin FWME2521RO-ULP Ultra Low Pressure RO Membrane

Compact 2521 RO Membrane for Water Vending and Pure Lab Systems

When your commercial RO system needs to fit inside a tight equipment room, water vending cabinet, or lab bench, the Franklin Water FWME2521RO-ULP reverse osmosis membrane delivers 400 GPD of permeate in a compact 2.5" x 21" element. This ultra-low-pressure 2521 membrane rejects 99.2% of dissolved salts at 150 psi, carries NSF/ANSI 61 certification, and handles feed water up to 2,000 mg/L TDS.

Quick Specs

• Membrane Type: Thin-Film Composite (TFC), Ultra-Low Pressure

• Element Size: 2.5" x 21" (standard 2521 format)

• Active Membrane Area: 14 ft² (1.3 m²)

• Permeate Flow Rate: 400 GPD (1.5 m³/d)

• Stabilized Salt Rejection: 99.2%

• Maximum Operating Pressure: 600 psi (4.14 MPa)

• Maximum Feed TDS: 2,000 mg/L

• Certification: NSF/ANSI 61

Key Features and Benefits

• This space-saving RO membrane element fits standard 2521 pressure vessels and works in water vending machines, small labs, and tight commercial equipment rooms where a full-length 2540 reverse osmosis membrane will not fit.

• As a low-pressure commercial RO membrane, the FWME2521RO-ULP operates at just 150 psi test pressure, reducing pump energy consumption and lowering operating costs compared to standard-pressure elements.

• 99.2% stabilized salt rejection strips dissolved solids from municipal, groundwater, and surface water sources, making this 2521 RO membrane suitable for feed water up to 2,000 mg/L TDS.

• NSF/ANSI 61 certified for drinking water system components, confirming the membrane meets health effects requirements for materials in contact with drinking water.

• 14 ft² of active membrane area produces 400 GPD of filtered permeate. As a small commercial reverse osmosis membrane, it supplies enough output for a single water vending station, office RO system, or lab pure water unit.

• Wide cleaning pH range of 1 to 13 allows aggressive chemical cleaning cycles to restore water flow through the membrane and extend service life in hard-water or high-fouling environments.

FWME2521RO-ULP Specifications

Applications

• Water vending machines and self-serve water refill stations

• Office and commercial building point-of-use drinking water

• Laboratory pure water preparation and analytical pre-treatment

• Boiler feed water and cooling tower makeup treatment

• Light commercial beverage and food preparation equipment

• Surface water and groundwater treatment for sources up to 2,000 mg/L TDS

• Pre-treatment stage for high-purity water production systems

Industries

• Commercial water treatment

• Food and beverage service

• Laboratories and research facilities

• Hospitality and office building management

• Light industrial process water

Buy the Franklin Water FWME2521RO-ULP Ultra Low Pressure RO Membrane Online from Cleanflow

This compact commercial RO membrane produces 400 GPD with 99.2% salt rejection and NSF/ANSI 61 certification, all at an ultra-low operating pressure that keeps pump energy costs down. 

Cleanflow Utility Supply Company is an authorized Franklin Water Treatment distributor. The FWME2521RO-ULP, compatible reverse osmosis system accessories, and replacement parts ship across Canada and the USA. Returns accepted within 30 days at returns.cleanflow.net.

Frequently Asked Questions

What systems does a 2521 RO membrane fit?

The 2521 is one of the smallest standard commercial reverse osmosis membrane sizes. It fits any 2.5" pressure vessel that accepts 2521-format elements. Common setups include compact commercial RO systems, water vending machines, and small lab water purification units. Confirm your existing membrane dimensions before ordering to make sure the housing matches.

What is the difference between a 2521 and a 2540 RO membrane?

Both are 2.5" in diameter, but the Franklin Water 2521 membrane is 21 inches long and the 2540 is 40 inches long. The shorter 2521 produces less permeate (400 GPD vs 750 GPD for the Franklin Water ULP models) but fits in tighter spaces. Choose the 2521 when your equipment room or membrane housing cannot hold a full-length element.

Is the FWME2521RO-ULP safe for commercial drinking water systems?

Yes. This Franklin Water 2521 ULP membrane carries NSF/ANSI 61 certification, which means it has passed health-effects testing for materials that come in contact with drinking water. That makes it suitable for office water dispensers, beverage equipment, and any system producing water for human consumption.

What feed pressure does this ULP RO membrane need?

The standard test pressure is 150 psi, but actual operating pressure depends on your feed water quality, temperature, and system setup. Because ultra-low-pressure RO membranes produce their rated output at lower pressures than standard commercial elements, they need smaller booster pumps and use less electricity over the membrane's service life.

What pre-treatment do I need for a 2.5 x 21 reverse osmosis membrane?

Feed water must have less than 0.1 mg/L free chlorine and an SDI (Silt Density Index, a measure of particle content in the water) below 5. At a minimum, install a carbon pre-filter to remove chlorine and a sediment filter to control particulates. Cleanflow stocks compatible reverse osmosis filters for both stages. For groundwater or surface water with elevated hardness, add a softener or antiscalant dosing system (a chemical treatment that prevents mineral buildup) to protect the membrane surface.