Pool chemistry is not complicated, but it is interconnected. Touch one number and three others move. The most common reason pools go green between visits isn't a missed shock — it's that one reading drifted out of range, dragged the next one with it, and by the time anyone looked at the water it was too late.
I tell every new tech who joins the company the same thing: don't memorize the numbers, understand the relationships. Chlorine doesn't work without pH in range. Salt cells don't work without stabilizer in range. Cloudy water is almost never about chlorine — it's about calcium or filtration. Once you see the system, the readings tell you a story.
This pillar covers every chemistry topic in our library, in the order a Florida pool owner will actually run into them.
Water chemistry is the 80/20 of pool ownership. Every problem a Florida pool owner will ever face — cloudy water, algae blooms, itchy skin, equipment corrosion, plaster etching, scale, even bad smells — traces back to a number that got out of range and stayed there.
The good news: there are only six numbers that really matter, and each one has a tight target range. Keep them in range and nearly every other problem becomes preventable. This pillar is your map to those numbers: what they are, why they matter, how to test them, and exactly what to do when they're off.
The six numbers that run your pool
Before you buy a single chemical, memorize these ranges. Every guide in this pillar drills into one of them.
| Parameter | Ideal range | What it does |
|---|---|---|
| pH | 7.4 – 7.6 | Controls chlorine effectiveness and swimmer comfort |
| Free chlorine | 1 – 3 ppm | Actually sanitizes the water |
| Total alkalinity | 80 – 120 ppm | Keeps pH from swinging |
| Cyanuric acid (CYA) | 30 – 50 ppm | Protects chlorine from UV |
| Calcium hardness | 200 – 400 ppm | Prevents etching and scale |
| Temperature | N/A | Affects chemistry reactions and comfort |
How water chemistry actually works
Think of your pool as a slow-moving reactor. Sunlight burns off chlorine. Bather load adds contaminants. Rain dilutes your chemicals and drops pH. Evaporation concentrates everything that's left. Your job as an operator is to dose the inputs to keep each parameter inside its target range, so the sanitizer can do its job and the water stays balanced against the pool surface.
The biggest mistake new pool owners make?Treating symptoms. They see algae and add chlorine. They see cloudy water and dump clarifier. They see green and panic-shock. But algae and cloudiness are almost always downstream of a chemistry number that's out of range — usually CYA too high or pH drifted up. Fix the root and the symptom evaporates.
Testing: the non-negotiable habit
You cannot manage what you do not measure. In Florida's climate, we recommend testing at least twice per week during summer and once per week in cooler months. Use a liquid reagent kit (Taylor K-2006 is our pick) or a high-quality test strip. Record the numbers — paper, phone, anywhere — because trends matter more than single readings.
Dive deeper: guides in this pillar
Each guide below takes one number and walks through it in plain English: