Pumptec 107SS vs DuPont SW30 membranes

Minimum concentrate-flow comparison

We often get asked about the Pumptec 107SS. It is a common topic in DIY watermaker discussions because it is compact, simple and capable of producing high pressure.

against DuPont minimum 1.0 GPM (3.8 L/min)

The best supplied Pumptec figure is only about one quarter of DuPont's minimum concentrate-flow guidance.

The DuPont requirement

DuPont's SW30 product sheet confirms that the SW30-2514, SW30-2521 and SW30-2540 are all nominal 2.5-inch seawater elements.

DuPont's midsize FilmTec design guideline lists the recommended minimum concentrate flowrate for 2.5-inch seawater elements as: 1.0 GPM (3.8 L/min)

Read the number carefullyThis is brine/concentrate flow only. Product water is additional.

That distinction matters. A pump must have enough flow to maintain the required brine flow across the membrane surface, while also allowing water to pass through the membrane as product water.

This is one of the reasons Water Makers Australia designs around correct membrane flow conditions.

Pumptec 107SS flow

All of the Pumptec 107SS cam options (.065, .075, .085 and .095) flow rates at 800 psi, all are well below 1.0 GPM (3.8 L/min).

More importantly, the Pumptec numbers are total pump flow. DuPont's number is minimum concentrate flow. So the Pumptec is already short before any product water is made.

The core issueIt is not about whether the pump can reach pressure. It is about whether the pump can move enough water through the membrane to operate it properly.

Why this matters

Running below DuPont's minimum concentrate-flow guidance does not mean the membrane will instantly fail. It may still produce water, but at a cost. The issue is that the membrane is being operated outside the recommended design envelope.

DuPont states that systems should be designed so each element operates within recommended limits, including minimum concentrate flowrate, to minimise fouling and help avoid mechanical damage. In practical terms, low concentrate flow can mean:

WarrantyDuPont's SW30 product sheet states that if operating limits and guidelines are not strictly followed, the limited warranty will be null and void.

This is why Water Makers Australia does not treat "it makes water" as the design standard. A marine watermaker should be built around the membrane manufacturer's operating requirements, so the membrane has the correct brine flow, correct pressure range and a better chance of long-term stable performance.

This is why Water Makers Australia does it differently

Water Makers Australia designs marine watermakers around proven membrane and pump matching, not just around achieving 800 psi.

Our systems use pump configurations with enough flow to properly support DuPont SW30 membranes. That means the membrane is not being starved of brine flow while trying to produce fresh water.

This approach is better because it helps maintain:

• Correct concentrate flow
• Stable membrane operation
• Lower fouling risk
• Better long-term production
• Better protection of the membrane
• A stronger technical and warranty position

It also means the system is designed for real marine use, with no compromises.

The takeawayA compact, low powered pump can look attractive, but if it cannot meet the membrane's minimum concentrate-flow guidance, it is the wrong foundation for a watermaker.

Conclusion

The Pumptec 107SS may make water, but it does not meet DuPont's minimum concentrate-flow guidance for the SW30-2514, SW30-2521 or SW30-2540.

That is the core issue.

The Pumptec 107SS is not the correct pump for use with DuPont SW30 seawater membranes. Water Makers Australia designs systems around the correct flow requirements for the membrane, because that is what protects performance, reliability and membrane life.

Matching a pump to a membrane, without the guesswork

Every Water Makers Australia system pairs the right pump, membranes and filters for your boat, built from standard, off-the-shelf parts and backed by 7-day support. Tell us your boat and your water needs, and we will size it properly.