Hydranautics seawater RO membranes
We supply Hydranautics (Nitto Group) seawater RO elements for partial or full replacement: the SWC4, SWC5 and SWC6 families in 8-inch and 4-inch sizes. Before quoting we check the installed model against the manufacturer's data.
WhatsApp: +34 655 099 909Updated: October 2026
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Models we supply
| Model | Active area | Permeate flow | Nominal salt rejection | Feed spacer (mil) |
|---|---|---|---|---|
| SWC4 MAX | 40.9 m² (440 ft²) | 27.3 m³/d (7,200 gpd) | 99.8% | 26–28 |
| SWC4-LD | 37.2 m² (400 ft²) | 24.6 m³/d (6,500 gpd) | 99.8% | 34 |
| SWC5 MAX | 40.9 m² (440 ft²) | 37.5 m³/d (9,900 gpd) | 99.8% | 26–28 |
| SWC5-LD | 37.2 m² (400 ft²) | 34.1 m³/d (9,000 gpd) | 99.8% | 34 |
| SWC6 MAX | 40.9 m² (440 ft²) | 25.0–50.0 m³/d (6,600–13,200 gpd) | 99.6% | 26–28 |
| SWC6-LD | 37.2 m² (400 ft²) | 22.7–45.5 m³/d (6,000–12,000 gpd) | 99.6% | 34 |
| SWC5-4040 (4-inch) | 7.9 m² (85 ft²) | 7.2 m³/d (1,900 gpd) | 99.7% | — |
| SWC5-LD-4040 (4-inch) | 7.4 m² (80 ft²) | 6.62 m³/d (1,750 gpd) | 99.7% | 34 |
| SWC4 / SWC5 1640 (16-inch) | 155 m² (1,670 ft²) | 109.8 / 136.3 m³/d | 99.8% | 28 |
Hydranautics states that the permeate flow of an individual element may vary by ±15%. SWC6 elements are listed in two versions, low pressure and high flow; the range covers both.
Sources: Hydranautics (Nitto Group) — SWC family brochure, Hydranautics — SWC5-4040 data sheet.
MAX or LD
MAX elements have 40.9 m² (440 ft²) of membrane and a 26–28 mil feed spacer. LD (Low Differential) elements have 37.2 m² (400 ft²) and a 34 mil spacer, which Hydranautics offers to limit colloidal fouling with conventional pretreatment. Replace like for like unless a projection supports the change: an LD vessel refitted with MAX elements runs with a different pressure drop.
Reference data: SWC4 MAX and SWC5 MAX
| Parameter | SWC4 MAX | SWC5 MAX |
|---|---|---|
| Permeate flow | 27.3 m³/d (7,200 gpd) | 37.5 m³/d (9,900 gpd) |
| Salt rejection | 99.8% nominal, 99.7% minimum | 99.8% nominal, 99.7% minimum |
| Active area | 40.8 m² (440 ft²) | 40.8 m² (440 ft²) |
| Maximum applied pressure | 83 bar (1,200 psig) | 83 bar (1,200 psig) |
| Maximum operating temperature | 45 °C | 45 °C |
| Maximum feed SDI (15 min) | 5.0 | 5.0 |
| Free chlorine | < 0.1 ppm | < 0.1 ppm |
Manufacturer's test conditions: 32,000 ppm NaCl, 55 bar (800 psi), 25 °C, 10% recovery, pH 6.5–7.0. DuPont, Toray and LG test at 8% recovery and pH 7 or 8, so compare data sheets with that in mind.
Sources: Hydranautics — SWC4 MAX data sheet, Hydranautics — SWC5 MAX data sheet.
What fails
Replacement causes are the same as for any seawater membrane: fouling in lead elements, scaling in tail elements, chlorine oxidation, and leaks at interconnectors or O-rings. The full symptom table is on the FilmTec membranes page.
What we need to quote
- Installed model from the element label (for example SWC5 MAX or SWC4-LD).
- Quantity and, for partial replacement, element positions.
- For a model or brand change: water analysis and operating data.
- Delivery country and address.
Documents
- Commercial invoice and packing list.
- Distributor invoice or confirmation identifying where the part was bought.
- Manufacturer's certificate of origin where the manufacturer issues one.
- Photos of the parts and their labels before dispatch.
- Air waybill (AWB) or bill of lading (B/L).
Have the equipment nameplate to hand?
Send a photo or the part number. We check the model and reply within 4 business hours.
Related pages
Frequently asked questions
Do you supply 4-inch Hydranautics elements?
Yes, for example SWC5-4040 and SWC5-LD-4040.
What is the difference between SWC5 MAX and SWC5-LD?
SWC5 MAX has 440 ft² of membrane and a 26–28 mil feed spacer. SWC5-LD has 400 ft² and a 34 mil spacer for feed water that fouls more easily.
Can Hydranautics elements be replaced with FilmTec, Toray or LG?
It can be done, but validate it with a projection and do not mix brands in one vessel without that support.
Where can I buy Hydranautics seawater RO membranes?
From Alisios. Send the nameplate photo or part number through the form on this page, by email to sourcing@alisios.co or on WhatsApp +34 655 099 909. We ship from Almería, Spain, to plants in Latin America, the Caribbean, the Mediterranean, North Africa and Egypt, and reply within 4 business hours.
What does an 8040 seawater RO membrane cost?
It depends on the model, the quantity and the delivery terms, so we quote each request. Send the model from the element label, the quantity and the delivery country, and we reply with a firm price within 4 business hours.