Ideal Pool Chemical Levels: The Ranges and Who Sets Them

For an outdoor home pool, aim for free chlorine of 2–3 ppm, pH 7.4–7.6, total alkalinity 80–120 ppm, calcium hardness 200–400 ppm and cyanuric acid (stabilizer) of 30–50 ppm. Those are the bands that satisfy both the CDC and the manuals of the three big salt-chlorinator brands. If you have a salt system, the salt level and sometimes the stabilizer target come from your own chlorinator’s manual, and the brands don’t agree.

Most charts give one set of numbers with no source. Below, every range names the document it comes from, and where the official numbers differ we show both and explain why.

Ideal pool chemical levels at a glance

Chlorine and pH are the first defense against germs that can make swimmers sick.

The “home target” column is the range that every source we checked accepts. The “limits” column shows the floors and ceilings that public pools must meet under CDC’s Model Aquatic Health Code (MAHC),² which many health departments build on.

The free-chlorine floors come from CDC’s page for home pool and hot tub owners, which also gives pH 7.0–7.8 and at least 3 ppm in hot tubs.¹ The other limits are from the 2024 MAHC, 5th edition (sections 5.7.3 and 5.7.4.4) and its Annex.^2,3 For salt, use our pool salt calculator, which lists each brand’s target.

Where the official numbers disagree, and why

We lined up CDC’s numbers with the water-chemistry tables in three salt-chlorinator manuals. All three manufacturers say their tables follow the Association of Pool and Spa Professionals (APSP), now the Pool & Hot Tub Alliance (PHTA).^4,5,6 We also added Trouble Free Pool, an owner forum whose numbers rank highly in search.⁹

Three differences matter in practice.

Public pools vs. your backyard pool

The MAHC is written for pools open to the public, such as those at hotels, apartment complexes and clubs. Its limits are legal floors and ceilings for a crowded pool, not targets: total alkalinity anywhere from 60 to 180 ppm meets the code.² The manuals give narrower bands meant to protect their equipment and your pool surface. For a home pool, aim inside the manuals’ bands while never dropping below CDC’s chlorine floor.

Same “APSP” label, different chlorine ranges

Hayward and Jandy print 1.0–3.0 ppm free chlorine, and Jandy warns that continuous exposure above 3.0 ppm may corrode pool metals.⁶ Pentair prints 2.0–4.0 ppm and puts its corrosion warning above 4.0.⁵ CDC’s Annex advises 2–4 ppm for public pools so the minimum is never missed.³ The manuals don’t say which APSP document or edition they used, and we could not read the standard itself: PHTA sells it, and its online copy is a page-image flipbook. The overlap, 2–3 ppm, meets every source at once.

Salt pools: the cell sets salt and stabilizer

The only special requirements for the AquaRite are the salt level and stabilizer.

Salt targets barely overlap: Hayward calls 3,200 ppm optimal, Pentair recommends 3,600 ppm and Jandy 3,000–3,500 ppm.^4,5,6 PHTA’s fact sheet on chlorine generators confirms that different units need different salt levels and tells owners to follow the manufacturer.⁷ Stabilizer splits the same way: Hayward and Pentair say 30–50 ppm, while Jandy asks for 50–75 ppm, rising to 75–85 ppm when the water runs above 85°F.⁶ Use the number in your own cell’s manual, and the salt calculator to turn it into bags.

What each number protects

Free and combined chlorine

Free chlorine is the sanitizer still available to kill germs. At 1 ppm, pH 7.5 and 77°F with no stabilizer, CDC says it kills E. coli O157:H7 in under a minute, but Cryptosporidium takes about 10.6 days.¹ Combined chlorine is chlorine already tied up with sweat and urine as chloramines; the MAHC tells public pools to act when it passes 0.4 ppm,² and the manuals want none.^5,6 Your test kit shows it as total chlorine minus free chlorine.

pH

CDC says 7.0–7.8 best balances germ-killing, pipe life and swimmer comfort: chlorine weakens as pH rises, especially above 8.0, while pipes corrode more below 7.0.¹ In an unstabilized pool, raising pH from 7.2 to 7.8 roughly halves hypochlorous acid, the fast-acting form of chlorine.³

Cyanuric acid (stabilizer)

Pentair’s guide says sunlight destroys 90% of unstabilized chlorine within two hours, which is why outdoor pools use cyanuric acid.⁵ The trade-off is that stabilizer binds chlorine. The MAHC Annex calculates about 30 times less hypochlorous acid at 2 ppm free chlorine with 50 ppm stabilizer than at 1 ppm with none, which is why CDC doubles the chlorine floor for stabilized pools.³ Public pools must stay at or below 90 ppm, and CDC advises no stabilizer in hot tubs.^2,1 Chlorine tablets (trichlor) and dichlor add stabilizer every time you use them.³

Total alkalinity, calcium hardness and balance

Total alkalinity is the buffer that stops pH from bouncing; too low and pH swings, too high and pH is hard to bring down.³ Calcium hardness of 200–400 ppm is preferred, says the Annex: too much causes cloudiness and scale, too little makes water that eats plaster and metal. For water above 90°F, as in a hot tub, it suggests 100–200 ppm.³ The saturation index combines pH, temperature, calcium, alkalinity and dissolved solids into one number; Hayward wants it between −0.2 and +0.2.⁴

Total dissolved solids

Everything that dissolves and never leaves, from minerals to sunscreen, adds to TDS. The Annex and PHTA use 1,500 ppm above the fill water as the point to partly drain and refill.^3,7 It is a convention, not a proven limit:

there are no known scientific data that substantiates any value as a maximum

Salt counts as TDS, so a salt pool’s baseline is the reading taken after the salt goes in; Pentair lists 3,000 to about 6,000 ppm including salt.^7,5

How often to test pool water

Here the sources differ most, because they are written for different situations.

CDC’s home-pool advice is the strictest: chlorine and pH at least twice a day, more often when many people swim.¹ The Annex also calls for a manual test after a major weather event at outdoor public pools.³

Use a DPD test kit if you can. CDC calls it the most accurate home option, says strips are less accurate, and warns that above 10 ppm chlorine the DPD color can bleach out and read falsely low.¹

Adjusting levels safely

Which product moves which number is set by the label and your equipment maker. Pentair’s and Jandy’s manuals name muriatic acid to lower pH and soda ash to raise it.^5,6 Hayward discourages dry acid (sodium bisulfate) for adjusting pH with its salt cells, especially in arid regions, because its by-products can build up and damage the cell.⁴

Doses depend on your pool’s volume, so find your gallons with the pool volume calculator before you add anything. Retest after the water has circulated rather than guessing a second dose. At the end of the season, our guide to when to close your pool explains why to balance the water before the cover goes on, and the pool and spa section has the rest of the season.