Salt Water Pools: How They Work

A salt water pool is a chlorine pool. That surprises a lot of people, so it’s worth saying first. The difference is where the chlorine comes from.

In a salt pool, salt dissolved in the water passes through a cell plumbed into the return line. The cell uses a low-voltage current to turn some of that salt into chlorine, which sanitizes the pool and then gradually turns back into salt. You add salt occasionally instead of adding chlorine every few days.

If you’re still deciding whether to convert, our post on saltwater vs chlorine pool maintenance compares the two. This page is about living with one.

The readings that matter

• Salt level. Most residential systems run at roughly 3,000–3,500 ppm, which is far less salty than the ocean. Your cell’s manual gives the exact range. Too low and the cell can’t make enough chlorine. Too high and some systems shut down or wear faster.
• Free chlorine, the same 1–3 ppm target as any pool. The cell’s output setting is what you adjust.
• pH. Salt cells tend to push pH up over time, so expect to add acid more often than you would in a tablet-chlorinated pool.
• Stabilizer and calcium, checked as for any outdoor pool. See the pool chemicals guide for targets.

Looking after the cell

The cell is the expensive part, and calcium is its main enemy. As water passes through, scale can build up on the plates and cut chlorine output.

• Inspect the cell a few times a season. White, crusty deposits on the plates mean it needs cleaning.
• Clean it with the method in the manufacturer’s instructions, often a diluted acid soak. Never scrape the plates.
• Keep pH and calcium in range. That’s what slows scaling.
• Cells wear out after several seasons of use. Lower chlorine output despite a clean cell and correct salt is usually the sign.

Through the Ontario year

Trade-offs to know about

Salt pools feel softer to many swimmers, and the steady low chlorine production avoids the peaks and dips of manual dosing. Those are real benefits.

There are costs too. Salt water can be harder on some natural stone coping, metal fixtures and certain equipment over time, so check your materials before converting, and rinse salt splash off nearby stone. The cell is a replacement part with a finite life, and that cost belongs in any comparison. And a salt system still needs testing. It reduces chores but doesn’t remove them.

Questions we get asked

Can I convert my existing pool to salt?

Most chlorine pools can be converted by adding a salt system to the existing plumbing, provided the equipment and materials are compatible.

What kind of salt should I use?

Pool-grade salt: high-purity sodium chloride without anti-caking additives or iodine. Ask at our retail store if you’re not sure which bag to buy.

Can you service my salt system?

Yes. Saltwater pool maintenance, cell cleaning and system repair are part of our pool service in Toronto.