Pool Chemistry Basics: What Every South Florida Homeowner Should Know

There are seven pool water measurements that matter. Get these right and your pool basically runs itself. Get even one chronically wrong and you're fighting algae, scale, or corrosion. Here's what each one is, the ideal range, and why South Florida is a little different.

1. Free Chlorine (FC)

The active chlorine killing bacteria and algae.

• Ideal: 2–4 ppm (chlorine pools), 1–3 ppm (salt pools)
• Too low: Algae blooms, cloudy water.
• Too high: Irritation, faded liners, bleached hair.

2. Combined Chlorine (CC) / Chloramines

“Used up” chlorine bonded with organic contaminants. This is what gives pools their strong chemical smell — contrary to myth, chlorine itself is nearly odorless.

• Ideal: Under 0.5 ppm
• Fix: Shock the pool to burn off chloramines.

3. pH

Acidity. Affects chlorine effectiveness and skin/eye comfort.

• Ideal: 7.4–7.6
• Above 7.8: Chlorine drops to ~20% effective, scale forms.
• Below 7.2: Corrodes equipment, irritates eyes.
• South Florida note: Pools drift high naturally — weekly muriatic acid additions are normal.

4. Total Alkalinity (TA)

pH buffer. Stabilizes pH against swings.

• Ideal: 80–120 ppm
• Too low: pH swings wildly with every addition.
• Too high: pH is “stuck” high, scaling risk.

5. Cyanuric Acid (CYA / Stabilizer)

Sunscreen for chlorine. Without CYA, South Florida sun burns off 90% of your chlorine in a day.

• Ideal: 30–50 ppm (chlorine), 60–80 ppm (salt)
• Over 80–100 ppm: Chlorine becomes “locked” and can't kill algae even at high readings. Requires partial drain to correct.

6. Calcium Hardness (CH)

Dissolved calcium. Too low eats plaster; too high scales surfaces.

• Ideal: 250–400 ppm
• South Florida note: Our tap water is already hard. Most South Florida pools run naturally toward the high end — scale prevention is constant.

7. Salt (if salt-chlorine)

• Ideal: 3,000–3,500 ppm (check your specific cell's target)

Bonus metric: Phosphates

Not always tested but critically important in South Florida. Over 500 ppb and algae gets the upper hand. More on phosphates.

How to test

For DIY owners, skip test strips — they're roughly accurate at best. Use a Taylor K-2006 or K-2006C kit. It measures everything except salt (salt needs a separate meter). Cost: $60–$80, lasts years with replacement reagents.

For our weekly-service clients, we test every visit with a professional digital photometer and adjust chemistry on site.

How often to test

• Free chlorine + pH: every 2–3 days in summer (DIY) or every week (serviced).
• TA, CH, CYA, salt: monthly.
• Phosphates: quarterly.

Would rather never think about any of this? Weekly service handles it.

Frequently Asked Questions