These target ranges reflect current industry guidance from the Pool & Hot Tub Alliance and Taylor Technologies. All parameters interact — correct them in order: alkalinity first, then pH, then chlorine.
Core Parameters
| Parameter | Minimum | Ideal Range | Maximum | Unit |
|---|---|---|---|---|
| Free Chlorine | 1.0 | 1–3 | 5 | ppm |
| Combined Chlorine | 0 | 0 | 0.5 | ppm |
| pH | 7.2 | 7.2–7.6 | 7.8 | pH units |
| Total Alkalinity | 60 | 80–120 | 180 | ppm |
| Calcium Hardness (plaster) | 150 | 200–400 | 500 | ppm |
| Calcium Hardness (vinyl/fibreglass) | 100 | 150–250 | 400 | ppm |
| Cyanuric Acid (standard pools) | 20 | 30–50 | 80 | ppm |
| Cyanuric Acid (salt pools) | 40 | 60–80 | 100 | ppm |
| ORP | 600 | 650–750 | — | mV |
| TDS (non-salt pools) | 0 | N/A | 2,000 | ppm |
Chemical to Raise or Lower
| Parameter | Raise With | Lower With |
|---|---|---|
| Free Chlorine | Liquid chlorine, cal-hypo, trichlor | Sodium thiosulfate (emergency only) |
| pH | Sodium carbonate (soda ash) | Muriatic acid or sodium bisulfate |
| Total Alkalinity | Sodium bicarbonate | Muriatic acid (aerate after) |
| Calcium Hardness | Calcium chloride | Partial drain and refill only |
| CYA | Cyanuric acid granules | Partial drain and refill only |
| Salt | Sodium chloride (pool salt) | Partial drain and refill only |
Notes
- Wait 4–6 hours after alkalinity adjustment before testing and adjusting pH.
- CYA cannot be reduced chemically — partial drain is the only remedy.
- Combined chlorine above 0.5 ppm requires shock treatment.
Sources:
- Pool & Hot Tub Alliance — Pool & Spa Operator Handbook, 2022