Salt Water Pool vs Chlorine Pool: What Actually Differs

A salt water pool is a chlorine pool. A salt chlorinator makes chlorine from dissolved salt inside your plumbing, so the water is sanitized by the same chemical either way. What actually differs is how the chlorine gets into the water and what comes with it: a salt pool drifts up in pH, a tablet pool builds up stabilizer, and the bills land in different years.

Everything below follows from that. For the wider picture, start at the salt water pools hub.

The differences side by side

The salt level sounds dramatic until you compare it. Seawater averages about 35 parts per thousand, roughly 35,000 ppm. A pool at 3,200 ppm is about 9% as salty.

Cost: why two sources that disagree are both right

River Pools lists “long-term costs equal traditional pools” as a drawback of salt. HomeGuide’s figures seem to say the opposite: chlorine chemicals at $175 to $750 a year against salt at $90 to $180. The gap is the cell.

River Pools puts a replacement cell at $700 to $1,100, lasting 3 to 7 years. Spread over its life:

• Cheapest case: $700 ÷ 7 years = $100 a year
• Most expensive case: $1,100 ÷ 3 years = about $367 a year

Now add that to the salt:

On consumables alone, salt is cheaper. Count the cell and the two ranges sit almost on top of each other. That is how both sources can be right. HomeGuide’s own cell figure, $600 to $1,000 every 3 to 6 years, tells the same story: $600 ÷ 6 = $100 up to $1,000 ÷ 3 = about $333 a year.

Neither total includes the control board, which River Pools says also lasts 3 to 7 years and costs $500 to $900, or the acid a salt pool goes through. None of our sources prices yearly acid use, so we are not printing a number.

Leave the pump out of the comparison. HomeGuide’s pump running cost of $30 to $150 a month, or $360 to $1,800 a year, applies to both pools.

Upfront, the quotes vary. HomeGuide says $600 to $2,200 to convert, including generator, salt and installation. River Pools says $1,700 to $2,500 plus salt. Leslie’s says salt chlorinators start at $1,000 and up. They price different equipment and installers. The full breakdown is on our page about the cost to install a salt water pool.

What drifts in a salt pool: pH

A working cell gives off hydrogen gas. Orenda explains that the bubbles aerate the water, drive off CO2 and raise pH. That is why salt pools drift up and why their owners reach for acid more often than they expect. See how to lower pH in a salt water pool and muriatic acid for a salt water pool.

What accumulates in a chlorine pool: cyanuric acid

Leslie’s says dichlor contains cyanuric acid, which “will increase residual CYA in the pool over time”. Trichlor, the 3 inch tablets automatic chlorinators use, is stabilized chlorine too. Orenda puts trichlor at only 45.8% chlorine by weight, with most of the rest cyanuric acid, so every tablet adds CYA.

CYA does not break down or leave. Orenda says only dilution or reverse osmosis lowers it. A pool fed on tablets for years eventually has to drain and refill part of its water, which is covered in how to reduce cyanuric acid.

A salt cell adds no CYA. You dose stabilizer once to your target and it stays until water leaves the pool. For that target, see cyanuric acid for a pool.

Why a salt pool can hold less chlorine

The chlorine you need depends on your CYA. Trouble Free Pool puts the minimum free chlorine for a salt pool at about CYA x 5%, against about CYA x 7.5% for a manually chlorinated pool. At a CYA of 40 ppm:

• Salt pool: 40 x 0.05 = 2 ppm free chlorine minimum
• Manual pool: 40 x 0.075 = 3 ppm free chlorine minimum

A cell feeds chlorine every hour the pump runs, so the level never sags between doses the way it does after a hand-added jug. That is why a salt pool can safely hold a lower floor. The full table is on the CYA chlorine chart.

Smell and eyes: correcting “no chlorine smell”

River Pools lists “No chlorine smell” as a salt pool advantage. The CDC says otherwise about what that smell is: “If you smell ‘chlorine’ at the place you swim, you are probably smelling chloramines.” Chloramines form when chlorine combines with sweat, urine, skin cells, deodorant and makeup, and they cause red, itchy eyes and skin irritation. They off gas into the air above the water and irritate the nose and respiratory tract, particularly indoors.

So a well-run salt pool smells less for the same reason a well-run chlorine pool smells less. Salt has nothing to do with it. A salt pool that smells of chlorine needs more chlorine, not less. We explain the fix in why a salt pool smells like chlorine. The CDC’s cheapest prevention applies to both pools: a one minute shower before swimming removes most of what makes chloramines.

Equipment and surfaces

The cell and its panel. The salt number on the panel is not measured. The cell reads conductivity and infers salinity, so scale, plate wear or cold water can move the reading while no salt moves anywhere. Hayward’s manual says its unit stops generating below 50°F. More on the hardware is under the salt cell hub.

Metal. River Pools lists corroding metal parts as a salt drawback.

Plaster. River Pools says salt wears plaster faster on concrete pools. River Pools builds fiberglass pools, which have no plaster, so weigh the claim with that interest in mind.

Stone. Travertine Mart describes spalling when salt water crystals are trapped beneath the surface of the stone, with unsealed natural travertine coping showing it after 2 years of daily exposure. It says an impregnating sealer gives reasonable protection for 5 to 10 years. Travertine Mart sells travertine, not sealer. See concrete sealer around salt water pools.

Vinyl liners. Latham says a salt pool’s liner lasts “just as long as it would in a chlorinated pool”, 8 to 12 years. Latham makes liners, and no source here contradicts it. More in how long a salt water pool liner lasts.

The rest of the risk list, including what salt does to plants and pets, is on dangers of salt water pools.

Which should you choose

Neither wins for everyone. These questions decide it:

• What is your pool and deck made of? Plaster and natural stone need a plan for salt. Vinyl, per Latham, does not change.
• Is your CYA already high from tablets? Switching to salt stops the climb. It does not lower what is there, only dilution does.
• How do you prefer to pay? Salt costs more up front and again in a lump every few years. Chlorine spreads the cost across the season.
• What chores would you rather do? Salt swaps adding chlorine for adding acid, watching pH and keeping the cell clean.
• How cold does your water get? A cell that stops below 50°F leaves you dosing by hand anyway.
• Is the pool under warranty? Leslie’s warns that converting may void the warranty from the manufacturer or your pool builder.

If salt comes out ahead, read how to convert a pool to salt water and price it against the cost to install a salt water pool.

Where to go next