Ideal Pool Chemical Levels by Pool Type
Most pool surfaces share pH 7.2–7.8 and total alkalinity 80–120 ppm. The big differences are calcium hardness (200–400 ppm for plaster, 150–250 ppm for vinyl, and a low number for some fiberglass) and the salt and stabilizer ranges for salt pools.
Always follow your product’s label directions. Pool and spa chlorine, bromine, shock and algaecides are EPA-registered pesticides: use products labeled for pool or spa use, and don’t swim or soak until levels are within the limit on your product’s label. If this page and a label disagree, the label wins.
On this page (10 sections)
Find your surface in the matrix, then check the source column. Where makers disagree, we say so. When your pool's manufacturer gives its own numbers, use those, because they can be part of the warranty. For the general chart that applies to any pool, see the pool chemistry chart.
The matrix: levels by pool type
"Source range" is what the source says. "Our target" is where we keep our calculator for that surface, which can be narrower. A blank or "we could not confirm" means we did not find a maker's number to cite.
| Pool type | pH | TA (ppm) | Calcium (ppm) | CYA (ppm) | Salt (ppm) | Free chlorine | Source |
|---|---|---|---|---|---|---|---|
| Plaster or pebble | 7.2–7.8 | 80–120 | 200–400 | 30–50 | Per cell manual | Per CYA (below) | National Plasterers Council |
| Vinyl liner | 7.2–7.8 | 80–120 | 150–250 | We could not confirm a maker range | Per cell manual | Per CYA (below) | Latham Pool (vinyl guide). Orenda notes most vinyl makers say 150–250. |
| Fiberglass | 7.2–7.4 (one builder) | 80–120 | Below 120 (one builder) | 30–50 | Per cell manual | 1–3 ppm (one builder) | Thursday Pools (fiberglass chemistry) |
| Salt water (any surface) | Same as surface | Often 60–90 for lower pH rise | Same as surface | Hayward AquaRite: 60–80. Hayward PowerSalt: 20–50. | AquaRite: 2,700–3,400, 3,200 ideal. IntelliChlor: 3,200–3,400. | Lower than a chlorine pool at the same CYA (our calculator) | Hayward and Pentair manuals; Orenda (TA) |
| Above-ground (vinyl) | 7.2–7.8 | 80–120 | 150–250 (our target) | 30–50 (our target) | Intex Krystal Clear: 2,500–3,500 | Per CYA | Use the vinyl row; makers' own tables: we could not confirm |
| Hot tub | 7.0–7.8 (CDC) | Our hot tub chart | Our hot tub chart | None (CDC) | Not applicable | At least 3 ppm (CDC) | CDC |
Free chlorine moves with stabilizer. The CDC says at least 1 ppm without cyanuric acid and at least 2 ppm with it. Our calculator sets the minimum at about 7.5% of CYA, and about 5% for a salt cell, so 3–5 ppm at CYA 40. The full table is on pool chlorine levels.
Plaster, pebble, and other cement finishes
The National Plasterers Council gives pH 7.2–7.8, total alkalinity 80–120 ppm, calcium hardness 200–400 ppm, and CYA 30–50 ppm. It says low calcium can deteriorate the finish and tile grout, and that water with pH below 7.2 is corrosive. Plaster is the surface where calcium matters most, because soft water pulls calcium out of the finish. The LSI calculator shows whether your pH, TA, calcium, and temperature lean toward etching or scale.
A brand new plaster finish has its own start-up rules. Follow the builder's start-up plan, not this page. We cover the standing numbers, not the first 28 days.
Vinyl liner pools
Latham Pool lists pH 7.2–7.8, TA 80–120 ppm, and calcium hardness 150–250 ppm for vinyl. Orenda Technologies adds a caution: it argues a fixed calcium range ignores water temperature, and it suggests lower alkalinity (about 60–70 ppm with salt systems) and relying on the LSI. We treat 150–250 ppm as the safe default for vinyl and stop there. Vinyl does not etch the way plaster does, so a calcium number that is a little off matters less. For an above-ground pool with a vinyl liner, see above-ground pool care.
Fiberglass pools
Fiberglass is where makers disagree most. Thursday Pools, a fiberglass builder, recommends pH 7.2–7.4, TA 80–120 ppm, calcium hardness below 120 ppm, CYA 30–50 ppm, and free chlorine 1–3 ppm. It says fiberglass does not need calcium for strength, and that too much calcium with high pH can do more harm than good. It also advises avoiding calcium-based chlorine (cal-hypo) and using a stain and scale control product. That is one builder. Some other pool guides give 200–400 ppm for every pool, so you will see conflicting numbers online. We could not confirm one industry-wide range for fiberglass, so use the number from your shell maker or installer. If you have a warranty, keep it in writing.
Salt water pools
A salt pool keeps the same pH, TA, and calcium targets as its surface. What changes is salt and stabilizer, and both come from the chlorinator's manual. Hayward's AquaRite manual gives salt 2,700–3,400 ppm, 3,200 ppm ideal, and stabilizer 60–80 ppm. Hayward's PowerSalt manual gives cyanuric acid 20–50 ppm. Pentair's IntelliChlor guide gives 3,200–3,400 ppm of salt. Because two cells from one maker can differ, read your model's manual. More on pool salt level and salt water pool care.
Above-ground pools
Most above-ground pools have a vinyl liner, so use the vinyl numbers: pH 7.2–7.8, TA 80–120, calcium 150–250. We could not confirm a water-chemistry table from Intex or Bestway for these. The Intex Krystal Clear saltwater manual (a third-party copy) gives 2,500–3,500 ppm salt with 3,000 ppm optimal; see Intex pool chemicals. Small pools change faster, so test more often.
Hot tubs
A hot tub is not a small pool. The CDC says pH 7.0–7.8, free chlorine at least 3 ppm, and no cyanuric acid. Temperature stays at or below 104 °F. See the hot tub chemistry chart for the full list.
How to use these numbers
- Find your surface in the matrix. If you don't know it, look at your pool's paperwork or ask the builder.
- Check your manual for pool and cell. If it has numbers, those win.
- Test chlorine, pH, TA, calcium, and CYA. A full kit or strips are fine; see the test kit comparison.
- Enter the test in the pool chemical calculator. Pick your pool's surface so the calcium and chlorine targets match.
- Fix one thing at a time, in the order the calculator shows, and retest.
Always follow the product label. It is a violation of federal law to use a pesticide product in a manner inconsistent with its labeling.
FAQ
What should calcium hardness be in a vinyl pool?
Latham Pool says 150–250 ppm for vinyl, and Orenda reports the same range from most vinyl makers. Vinyl cannot etch the way plaster does, so a small miss is less costly than in plaster.
What chemical levels does a fiberglass pool need?
One fiberglass builder gives pH 7.2–7.4, TA 80–120 ppm, calcium below 120 ppm, CYA 30–50 ppm, and free chlorine 1–3 ppm. Other sources give different calcium numbers, so follow your shell maker's guidance.
What should calcium be in a plaster or pebble pool?
The National Plasterers Council gives 200–400 ppm. Low calcium can deteriorate the finish and tile grout.
What are the right levels for a salt water pool?
Use your cell's manual. Hayward's AquaRite manual says 2,700–3,400 ppm of salt with 60–80 ppm of stabilizer. Pentair's IntelliChlor guide says 3,200–3,400 ppm of salt.
Are the levels different for an above-ground pool?
Not by much if it has a vinyl liner. Use the vinyl row, and test often, since small pools change faster.
Sources
- National Plasterers Council, Water chemistry (pH 7.2–7.8, TA 80–120, calcium 200–400, CYA 30–50): nationalplastererscouncil.com
- Latham Pool, Balance the water chemistry in your vinyl liner pool (pH, TA, calcium 150–250): lathampool.com
- Orenda Technologies, Understanding vinyl liner pools (most makers 150–250; LSI caution): blog.orendatech.com
- Thursday Pools, Fiberglass pool water chemistry (one builder's numbers): thursdaypools.com
- Hayward, AquaRite manual (salt and stabilizer): PDF. Hayward PowerSalt manual (CYA 20–50): PDF
- Pentair, IntelliChlor Quick Start Guide (salt 3,200–3,400): PDF
- CDC, Home pool and hot tub water treatment and testing (FC, pH, CYA in hot tubs): cdc.gov
- Intex Krystal Clear Saltwater System owner's manual (third-party copy): manuals.plus
- Our own targets and method: methodology.