Ideal Pool Chemistry Levels
Every pool reading, its target range, and the calculator that fixes it. Balance in the right order, from the top down, and the water mostly takes care of itself.
| Reading | Ideal range | What it does | Fix it |
|---|---|---|---|
| Free chlorine (FC) | About 7.5% to 12% of your CYA | The active sanitizer. Set by your CYA, not a fixed number. | Chlorine calculator |
| pH | 7.4 to 7.6 | Swimmer comfort and chlorine effectiveness. | pH calculator |
| Total alkalinity (TA) | 80 to 120 ppm | Buffers pH so it does not swing. | Alkalinity calculator |
| Cyanuric acid (CYA) | 30 to 50 ppm (60 to 80 for salt) | Protects chlorine from sunlight; sets the FC target. | Cyanuric acid calculator |
| Calcium hardness (CH) | 200 to 400 ppm (150 to 250 vinyl) | Protects surfaces; too low corrodes, too high scales. | Calcium hardness calculator |
| Salt | 2,700 to 3,400 ppm (salt pools) | Feeds the salt chlorine generator. | Salt calculator |
| Combined chlorine (CC) | 0.5 ppm or less | Used-up chlorine. High means shock the pool. | Shock calculator |
| Saturation index (LSI) | -0.3 to +0.3 | Overall water balance: corrosive vs scaling. | Saturation index calculator |
Balance in this order
The readings depend on each other, so the order matters. Set total alkalinity first, because it buffers pH. Then dial in pH. Next, get cyanuric acid into range, since it sets your free chlorine target. Then keep free chlorine where it should be for that CYA. Finally, check overall balance with the saturation index.
None of these mean anything without your pool volume, which every dose depends on. Start from the pool volume calculator if you are not sure of your gallons.
Frequently asked questions
What are the ideal pool chemistry levels?
pH 7.4 to 7.6, total alkalinity 80 to 120 ppm, calcium hardness 200 to 400 ppm, and cyanuric acid 30 to 50 ppm for a chlorine pool or 60 to 80 for a salt pool. Free chlorine is not a fixed number; it should be about 7.5 to 12 percent of your CYA. Combined chlorine should stay at or below 0.5 ppm.
What order should I balance pool chemistry in?
Start with total alkalinity, since it buffers pH. Then set pH. Then make sure cyanuric acid is in range, because it sets your free chlorine target. Then keep free chlorine where it should be for that CYA. Calcium hardness and overall balance come after the basics are stable.
Why is there no single ideal free chlorine level?
Because cyanuric acid changes how strong your chlorine is. More CYA means you need more free chlorine for the same sanitizing power. That is why free chlorine is given as a percentage of CYA rather than a fixed number, and why knowing your CYA comes first.
How often should I test pool chemistry?
Test free chlorine and pH every day or two in swim season. Test alkalinity, calcium hardness, and cyanuric acid weekly or when something seems off. Always test before adding chemicals, and retest after, since dosing against an old or inaccurate reading is the most common mistake.