Saltwater Pool Maintenance

A salt pool takes about as much time as a chlorine pool. What changes is where the time goes. You stop hauling chlorine every week, you start watching pH every week, and you take on one piece of equipment that has to be inspected on a schedule or it dies years early.

The routine, at a glance

What a salt pool needs that a chlorine pool does not

Acid, on a schedule. pH climbs in every salt pool, every season, and it is not a fault. Orenda’s explanation is that hydrogen gas bubbling off the cell aerates the water, and that aeration drives dissolved carbon dioxide out. Losing CO2 raises pH. The older explanation, that sodium hydroxide from the cell is the culprit, is the wrong one. Either way, letting pH sit high is what grows scale on your cell plates.

Hayward’s AquaRite manual puts pH between 7.2 and 7.8. Most salt pool owners add a small dose of muriatic acid every week or two, not a large dose once a season.

A cell inspection. Hayward asks you to inspect the cell every three months, or whenever you clean the filter. Five minutes, and it decides whether you get three years out of the cell or seven.

More stabilizer than you are used to. This is where converts get caught. Hayward’s water balance chart asks for 60 to 80 ppm with 80 as the target. Trouble Free Pool recommends 60 to 90 ppm for a salt water chlorine generator pool, against 30 to 60 ppm for a pool run on liquid chlorine. Those ranges do not agree perfectly and we are not going to pretend they do. Follow your own manufacturer, because your warranty follows your manual. More on salt water pool stabilizer and cyanuric acid for pools.

Salt, occasionally. Salt is not consumed. It leaves only with water: splash-out, backwash, filter cleaning, leaks and draining. A pool that needs a bag every couple of weeks has a leak, not a chemistry problem.

What it needs less of

Weekly chlorine dosing. The cell does that continuously while the pump runs. This is the real labor saving.

Chlorine tabs. The default habit from chlorine pools, and the fastest way to wreck a salt pool. Orenda points out that “trichlor is only 45.8% chlorine (by weight). The majority of it is cyanuric acid.” Your pool is already meant to sit at 60 to 80 ppm stabilizer. Tabs on top of that push it past the point where chlorine works, and the only ways back down are draining and diluting, which Orenda calls the most economical and practical option, or reverse osmosis.

Shock, most weeks. You will still shock occasionally, but not on a calendar. See salt water pool shock for when it is warranted and why the boost button is not doing it.

Weekly

Two tests, ten minutes, then the physical work.

pH. Target 7.2 to 7.8 per Hayward. Add muriatic acid in front of a return with the pump running, retest the next day. Small and often beats large and occasional, because a big acid slug drops alkalinity harder than you intended.

Free chlorine. Hayward’s chart asks for 1.0 to 3.0 ppm. Read it alongside your stabilizer, because Trouble Free Pool’s point is that the free chlorine you must hold depends on your stabilizer level and rises as stabilizer rises. Too low for the stabilizer you carry and you get algae. So 1.0 ppm at 80 ppm stabilizer is not the same sanitizer as 1.0 ppm at 30. Run the upper half of the chlorine range if your stabilizer sits at the upper end of theirs.

The physical work. Baskets, skimming, and brushing the walls, steps, corners and behind the ladder. Algae starts where water does not move.

If chlorine is low, the reflex is to raise the output percentage. That works the cell harder for the same hours. More pump hours at a lower percentage usually gets the same chlorine and a longer cell.

Monthly

Run the full panel: salt, stabilizer, total alkalinity, calcium hardness. Alkalinity belongs at 80 to 120 ppm per Hayward, and it is what stops your weekly acid dose from swinging pH around.

For salt, do the thing almost nobody does: write down both numbers. The display’s salinity, and a titration test on a fresh sample taken away from the returns. Track them month over month. The gap between them is the most useful diagnostic you own, and the reason is on salt levels and testing.

Doses only mean anything if you know your gallons. If your volume is a builder’s estimate, fix it once with the pool volume calculator, and the pool salt calculator will give you a bag count you can trust.

Every three months: the cell

Shut the system off, close the valves, pull the cell, and look at the plates with a flashlight. Clean plates are dark grey and smooth. Scale is white crust bridging between them.

Hayward’s instruction is to try a high pressure garden hose first on mild deposits. Only if that fails do you go to acid, at 4 parts water to 1 part muriatic acid, soaked “for a few minutes” and rinsed. Hayward capitalizes the safety rule and so will we: ALWAYS ADD ACID TO WATER, NEVER ADD WATER TO ACID. Never put a metal tool between the plates, because it scratches the coating and the coating is the cell. Full procedure on how to clean a salt cell.

If the plates are clean and the panel still complains, do not clean it again. Acid soaking a clean cell removes coating for nothing. Go to the diagnostic order on salt cells.

Spring

The order matters at opening, because cold water lies to you.

Your panel has no salt sensor. It measures how easily current crosses the cell and infers a salinity number with a temperature correction. Cold water conducts less readily, and Orenda notes that most salt cells alarm or shut off between 55 and 59°F, while Hayward states its own unit “automatically stops generating when the pool water temperatures drops below 50ºF.” Model specific, so check yours.

So the panel may show low salt and refuse to generate in water holding exactly as much salt as it did in October. Test the water, do not add salt to satisfy a display. Then, in order: balance pH and alkalinity, get stabilizer into range, confirm salt with a test, and only then turn the generator up.

Stabilizer is slow. HTH’s instructions are to add it to the skimmer with the pump running, not backwash for 48 hours, and wait 24 to 48 hours of circulation before retesting. Do that at opening, not in July.

Fall

Balance the water first, then the equipment. What happens to the cell depends on whether you freeze, and the reading problem above gets worse as the water cools. That procedure is on how to winterize a salt water pool.

What the year costs

HomeGuide puts DIY saltwater maintenance at roughly $45 a month, professional service at $80 to $95 a month, and overall pool maintenance at $960 to $1,800 a year. Most of the DIY figure is acid and the occasional bag of salt, and the chemicals you actually need list is shorter than what the store will sell you. The expensive line item is the cell, which is what the three month inspection protects.

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