Water Purification Supplies Mb-4021-Lp Low Pressure RO Membrane 4.0" X 21"

The Water Purification Supplies MB-4021-LP (part no. 4021-LP-WPS) is a 4.0" x 21" low pressure spiral-wound reverse osmosis membrane element rated at 950 GPD with 99.3% nominal salt rejection. It is designed for brackish and municipal feed water, balancing high salt rejection with low operating pressure. Supplied wholesale by All For Water.

Specifications & operating limits

• Nominal / minimum salt rejection: 99.3% / 99%
• Permeate flow: 950 GPD (3.6 m³/d), ±15%
• Active membrane area: 39 ft² (3.6 m²)
• Feed spacer: 28 mil
• Test conditions: 1,500 ppm NaCl, 150 psi (10.3 bar), 77 °F (25 °C), 8% recovery, pH 7 – 8
• Max. operating pressure: 600 psi (41.4 bar)
• Max. feed flow: 3.6 m³/h (15.9 GPM)
• Max. operating temperature: 113 °F (45 °C)
• Max. pressure drop per element: 15 psi (1.0 bar)
• pH range: 2 – 11 continuous, 1 – 13 during cleaning
• Feed free chlorine: <0.1 mg/L
• Max. feed SDI (15 min): 5
• Dimensions: length 21" (533 mm), diameter 3.9" (99 mm), permeate tube OD 0.75" (19 mm), tube extension 1.05" (26.7 mm)

Salt rejection should be verified after 24 – 48 hours of continuous operation; results depend on feed water quality and operating conditions. Request a quote for current wholesale pricing and volume discounts.