What membrane element sizes do you stock?
We stock 4040 (4-inch x 40-inch), 4021 (4-inch x 21-inch), 8040 (8-inch x 40-inch), and 8080 (8-inch x 80-inch) elements. The 8040 is the most common industrial size, providing roughly 400 square feet of active membrane area per element. Element selection must match your existing pressure vessel inner diameter and element length.
What is the difference between brackish water and seawater membrane elements?
Brackish water elements operate at 150-225 PSI and are designed for feed TDS up to 10,000 ppm, achieving 97-99% rejection. Seawater elements operate at 800-1,200 PSI for source water above 10,000 ppm TDS, with rejection rates of 99-99.7%. Using a brackish element on seawater feed will result in poor rejection and rapid membrane failure.
What brands of replacement elements do you supply?
We supply FILMTEC (DuPont), Hydranautics (Nitto), Toray, and CSM replacement elements. FILMTEC BW30 and SW30HR series are our highest-volume industrial SKUs. Hydranautics ESPA and CPA series are popular in food and pharmaceutical applications. All elements are shipped in original manufacturer packaging with full traceability documentation.
What is a low-fouling membrane and when should I specify one?
Low-fouling elements use a modified polyamide surface coating that reduces adhesion of organic matter, colloids, and biofilm. They are worth specifying when your feed SDI exceeds 4, when you have elevated TOC above 2 ppm, or when you have had recurring biofouling problems on standard elements. They typically cost 20-35% more but can double cleaning intervals in difficult water.
How should replacement membrane elements be stored before installation?
Store elements in their original sealed bags at 40-77 degrees F, away from direct sunlight and ozone sources. Elements stored dry should be soaked in clean water for 1-2 hours before installation. Wet-preserved elements (in 1% sodium bisulfite solution) should be flushed thoroughly before startup. Never allow membrane elements to freeze.
Can I mix membrane brands within the same pressure vessel?
Mixing brands within a vessel is not recommended. Different manufacturers have slightly different element lengths and end cap tolerances, which can cause bypass flow around o-rings and reduced overall rejection. If you need to replace only some elements in a vessel, use the same brand and model as the remaining elements, or replace all elements in that vessel simultaneously.