Frequently Asked Questions About Watermaker Membrane Cleaning

Do I need to clean my membrane every time after pickling my watermaker?

No. If your watermaker was properly pickled and stored according to the manufacturer’s instructions, the membrane should not require chemical cleaning before returning it to service.

After recommissioning the system and performing a thorough flush, the membrane should produce water with the same performance and water quality it had before storage. Chemical cleaning is only necessary if there is a specific performance issue.

Do I need to use both SC-2 and SC-3 to clean my membrane?

No. SC-2 and SC-3 are designed to treat two different types of membrane fouling.

• SC-2 is used to remove biofouling, such as organic growth and biological contamination. This is the most common type of fouling found in marine watermakers.
• SC-3 is used to remove mineral scale deposits, such as calcium and other inorganic buildup. Scaling is much less common in boat-based watermakers.

Use the cleaning chemical that matches the problem affecting your membrane. In most cases, only one cleaner is needed.

Does SC-2 work better than SC-3?

Neither cleaner is better than the other—they simply address different problems.

SC-2 is formulated to remove biological fouling, while SC-3 is formulated to dissolve mineral scaling. Choosing the correct cleaner depends on what is causing the loss of membrane performance.

How do I know when my membrane needs cleaning?

Before cleaning the membrane, make sure the rest of your watermaker is operating correctly. A worn high-pressure pump, clogged pre-filters, or incorrect operating pressure can all reduce production and make the membrane appear to be the problem.

If the system is operating to specification but you notice:

• Reduced freshwater production,
• Product water quality has declined, or
• Total dissolved solids (TDS) readings consistently exceed 500 PPM,

then a membrane cleaning may be appropriate before considering replacement.

Does SC-2 also pickle or preserve my membrane?

No. SC-2 is a cleaning chemical, not a storage or preservation solution.

If you’re preparing your watermaker for storage, use the manufacturer’s recommended preservation product, such as SC-1 or PG-50, depending on your system and storage requirements.

How often should I chemically clean my watermaker membrane?

There is no scheduled maintenance interval for chemical membrane cleaning on most boat-based watermakers.

A properly maintained membrane may never require chemical cleaning. If you find yourself cleaning the membrane multiple times during its service life, it’s usually a sign that another issue—such as poor flushing practices, contaminated source water, inadequate filtration, or an equipment problem—is causing recurring fouling.

Does the cleaning solution clean the entire watermaker or just the membrane?

The cleaning solution circulates through the watermaker and cleans the wetted components of the system, including the reverse osmosis membrane. While the membrane is the primary component being treated, the cleaning process also helps remove deposits from other internal passages that come into contact with the cleaning solution.

Do most customers use SC-2 or SC-3?

Most customers use SC-2 because biofouling is the most common cause of membrane performance loss in marine watermakers.

SC-3 is typically used only when mineral scaling has been identified as the cause of reduced performance.

Is it a good idea to keep SC-2 or SC-3 onboard as a spare?

Yes. Keeping membrane cleaning chemicals onboard is a good idea, especially for boat owners who cruise for extended periods or travel to remote locations.

Since SC-2 and SC-3 treat different types of membrane fouling, the best spare depends on your watermaker’s operating conditions and the type of problem you’re most likely to encounter. If you’re unsure which cleaner you may need, we’re happy to help you determine the best option for your system.