How to Balance Your Pool Water: A Simple Chemistry Guide
Cloudy or itchy water usually comes down to a few numbers. Here is what to test, the ideal ranges for chlorine, pH, and alkalinity, and the order to adjust them in.
Cloudy, green, or itchy water almost always comes down to a handful of numbers being out of range. You do not need to be a chemist - you need to test a few values and adjust them in the right order. Here is the short version.
The numbers that matter
- Free chlorine (FC) - the sanitizer that keeps water safe. Too low and algae and bacteria take over.
- pH - how acidic or basic the water is. It affects comfort, chlorine effectiveness, and your equipment.
- Total alkalinity (TA) - a buffer that keeps pH stable.
- Calcium hardness (CH) and cyanuric acid (CYA) - CYA protects chlorine from sunlight; CH protects surfaces and equipment.
The ideal ranges
As a general guide: free chlorine 1-3 ppm (higher if your CYA is high), pH 7.2-7.8, total alkalinity 80-120 ppm, calcium hardness 200-400 ppm, and CYA 30-50 ppm for an outdoor pool. Your exact targets depend on your pool surface and sanitizer.
Adjust in the right order
Order matters because each value affects the next. Start with total alkalinity, since it stabilizes pH. Then set pH. Then bring chlorine to target. Adjusting pH before alkalinity, or chasing chlorine while pH is way off, just sends you in circles.
Test regularly and log it
Water chemistry drifts with heat, rain, and use. Testing two or three times a week in season - and writing the results down - lets you catch a problem while it is still a small dose away, not a green pool.
Get the exact dose
The hard part is turning a reading into "how much do I add for my pool." That is what PoolLog does: enter your test results and it calculates the precise dose for your pool volume and sanitizer type, then stores every reading so you can see trends across the season.