The SpiroPure SP-SW2521 Seawater Desalination Commercial Reverse Osmosis Membrane Replacement 2.5 x 21 is a high quality, high salt rejection replacement membrane filter cartridge. The SP-SW2521 seawater ro membrane offers an extremely high salt rejection rate, making it the perfect choice for treating sea water and other high sodium applications. SpiroPure’s seawater filtration membranes are durable and reliable replacement seawater filters. Choose SpiroPure’s Seawater Desalination Membrane as a compatible replacement for the models listed below.
Sea Water Desalination RO Membrane Recovery Specifications:
- Nominal Size: 2.5" x 21"
- Certification: NSF 61 certified
- Salt Rejection Rate: 99.5%
- Average Permeate ±15%: 270 GPD @ 800 PSI
- Feedwater NaCl: 32,000 ppm
- Fresh Water Recovery Rate: 4%
- Feed Spacer: 28 mm
- Maximum Recommended NaCl: <40,000 ppm
- Maximum Operating Pressure 1,000 PSI
SP-SW2521 High Rejection Membrane common applications:
- Seawater desalination
- Marine applications
- On-board watermakers for drinking water from seawater
- Watermaker RO Systems
- Yachts, boats, cruise ships, off-shore platforms, resorts
SW salt water/seawater membrane compatible model numbers:
- SE1-2521
- Dupont Filmtec SW30-2521
Additional Information
Seawater Membranes Are Shipped Wet
An important industry practice for seawater desalination RO membranes is to have them "shipped wet." After being tested to industry standards, our membranes are preserved for protection during shipping and for future use. The preservative is food-grade, and is found within the membrane itself and not in the air-tight packaging. The preservative creates a moist environment for the filter media, allowing the permeability and performance to be maintained by preventing biological growth during storage as well as providing a longer shelf-life of one-year from the manufacturing date printed on the package.
The sea water membrane price compared to other SpiroPure 2521 elements reflects the specialized composite polyamide for high-pressure environments.
FAQs on 2521 Seawater Filters
What is a 2521 seawater membrane used for?
A 2521 seawater membrane treats water with very high salinity, such as ocean or brackish coastal sources, to produce potable water. The SpiroPure SP-SW2521 is commonly used in marine watermakers, yachts, boats, cruise ships, off-shore platforms, and resorts.
Is the SpiroPure SP-SW2521 compatible with FilmTec SW30-2521?
Yes. The SpiroPure SP-SW2521 seawater RO membrane is manufactured as a compatible replacement for the Dupont Filmtec SW30-2521 and SE1-2521, matching their 2.5" x 21" size and high salt rejection specifications for seawater desalination.
What does 99.5% salt rejection mean in a seawater RO membrane?
A 99.5% salt rejection rate or sea water membrane recovery rate means the SP-SW2521 blocks 99.5% of dissolved salts from passing through, tested against 32,000 ppm feedwater NaCl, roughly typical ocean salinity. This high rejection rate is what allows the membrane to produce genuinely fresh water from seawater.
Why does a seawater RO membrane need high pressure?
Seawater's high salt concentration creates strong osmotic pressure that the system must overcome to push fresh water through the membrane. The SP-SW2521 requires up to 1,000 PSI maximum operating pressure, far more than a brackish water membrane needs for its lower-salinity feed.
Can I use a brackish water RO membrane for seawater?
No. Brackish water membranes like the SP-BW2521 are rated for feedwater up to 10,000 ppm NaCl, well below seawater's typical 32,000+ ppm salinity, and aren't built to withstand the pressure seawater desalination requires. Use a dedicated seawater membrane like the SP-SW2521 instead.
How much does the SpiroPure SP-SW2521 cost?
The sea water membrane price for the SpiroPure SP-SW2521 compared to other SpiroPure 2521 elements reflects its specialized composite polyamide construction built for high-pressure, high-salinity environments, while still costing a fraction of brand name membranes. See this page for current pricing.
