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Pool Chemical Levels Chart
Use this pool chemical levels chart to see where your water should sit when it comes to chlorine, pH, alkalinity, calcium, stabilizer, and salt. There is no one number for free chlorine, since the right amount hinges on how much stabilizer your water holds.
Ideal pool chemical levels
| Reading | Aim for | Still fine | Too low means | Too high means |
|---|---|---|---|---|
| Free chlorine | 3 to 5 ppm (parts per million) at 30 CYA | Set by your stabilizer: see the chlorine by CYA table | Algae and germs get a foothold | Red eyes, faded swimwear; swim once it is back in your stabilizer range |
| pH | 7.4 to 7.6 | 7.2 to 7.8 | Stinging eyes, etched plaster | Weaker chlorine, scale, cloudy water |
| Total alkalinity | 80 to 120 ppm | 60 to 180 ppm | pH swings | pH keeps rising |
| Calcium hardness | 200 to 400 ppm | 100 to 300 ppm in vinyl or fiberglass | Soft water eats plaster | Scale and cloudy water |
| Stabilizer (CYA) | 30 to 50 ppm | 70 to 80 ppm with a salt cell | Sun burns off chlorine | Chlorine needs to run higher |
| Salt (salt pools) | 3,000 to 3,500 ppm | 2,700 to 3,400 ppm, or your cell's label | Cell stops making chlorine | Salty taste, wear on metal |
When you test your water, most results come back in parts per million (ppm). That is simply a measure of how much of each chemical the water carries.
Download: Chart (PNG) · Chart (SVG) · Ranges (CSV) · Weekly test log (CSV) · Print this page
Stabilizer sets your chlorine target
Stabilizer goes by a couple of other names too: cyanuric acid, or CYA. Its job is to shield the chlorine in your water. So the more stabilizer you have, the more free chlorine your pool needs to stay clean.
With stabilizer at 30 ppm, hold free chlorine between 3 and 5 ppm. At 40 ppm, go up to 4 to 6 ppm. Salt pools tend to sit at 70 to 80 ppm stabilizer, so their chlorine needs to run even higher.
| Stabilizer (CYA) | Never below | Keep it at | Shock level |
|---|---|---|---|
| 0 ppm | 1 ppm | 2 to 4 ppm | 10 ppm |
| 20 ppm | 2 ppm | 2 to 4 ppm | 10 ppm |
| 30 ppm | 2 ppm | 3 to 5 ppm | 12 ppm |
| 40 ppm | 3 ppm | 4 to 6 ppm | 16 ppm |
| 50 ppm | 4 ppm | 6 to 8 ppm | 20 ppm |
| 60 ppm | 5 ppm | 7 to 9 ppm | 24 ppm |
| 70 ppm | 5 ppm | 8 to 11 ppm | 28 ppm |
| 80 ppm | 6 ppm | 9 to 12 ppm | 32 ppm |
| 90 ppm | 7 ppm | 10 to 14 ppm | 36 ppm |
| 100 ppm | 8 ppm | 11 to 15 ppm | 40 ppm |
Free chlorine follows the Trouble Free Pool chart. Salt pools run stabilizer at 70 to 80 ppm.
Adjusting pool chemical levels
The amounts below assume a 10,000 US gallon pool. Got 20,000 gallons? Double them. For 5,000 gallons, halve them.
| Product | What it changes in 10,000 gallons | Amount | Metric |
|---|---|---|---|
| Liquid chlorine 12.5% | Free chlorine up 1 ppm | 10 fl oz | 305 mL |
| Liquid chlorine 10% | Free chlorine up 1 ppm | 13 fl oz | 380 mL |
| Cal-hypo 65% | Free chlorine up 1 ppm | 2.1 oz | 60 g |
| Dichlor 56% (adds 0.9 ppm stabilizer) | Free chlorine up 1 ppm | 2.4 oz | 70 g |
| Trichlor 90% in a floater (adds 0.6 ppm stabilizer) | Chlorine fed by tablets, per 1 ppm | 1.5 oz | 40 g |
| Liquid chlorine 12.5% | Shock, free chlorine up 10 ppm | 102 fl oz | 3.03 L |
| Muriatic acid 31.45% | pH 7.8 down to 7.5 | 9 fl oz | 270 mL |
| Dry acid 93.2% | pH 7.8 down to 7.5 | 12 oz | 350 g |
| Soda ash | pH 7.2 up to 7.5 | 1 lb 1 oz | 495 g |
| Baking soda | Alkalinity up 10 ppm | 1 lb 6 oz | 635 g |
| Muriatic acid 31.45% | Alkalinity down 10 ppm | 26 fl oz | 755 mL |
| Cyanuric acid | Stabilizer up 10 ppm | 13 oz | 380 g |
| Calcium chloride 77% | Calcium hardness up 10 ppm | 1 lb 3 oz | 545 g |
Chemicals are sold in fixed jug and bag sizes. Buy the whole thing, pour out just what your pool calls for, and keep whatever is left for later.
Add half, let the pump mix it, test again, then add the rest: 30 minutes for chlorine, acid and soda ash, a day for baking soda and calcium, and up to a week for stabilizer. Acid always goes into water, not water into acid, and acid never meets chlorine. For your own gallons, use the pool chemical calculator or print the dosage chart.
Adding chemicals safely
- 1. Keep the pump running whenever you add something, so it pushes the chemical all through the pool.
- 2. Work with one chemical at a time, and pour it near a return jet, the spot where the water comes back into the pool.
- 3. Acid goes into water, not the other way around. Pouring water into acid can cause splashing.
- 4. Acid and chlorine should never touch each other.
- 5. Wait 30 minutes after dosing with acid or soda ash before you check pH again. The reading needs that time to settle.
Liquid chlorine at normal levels means you can hop back in after roughly 30 minutes. After a shock, hold off until free chlorine is back in the range the table gives for your stabilizer, and never above 10 ppm.