Pool Water Chemistry 101: What Every Homeowner Should Know

Pool water chemistry can seem intimidating, but it does not have to be. At its core, you are managing just a handful of measurements — and once you understand what each one does, keeping your water balanced becomes second nature.

pH: The Foundation of Everything

pH measures how acidic or basic your water is on a scale of 0–14. Pool water should be slightly basic, between 7.2 and 7.6. When pH is too low (acidic), it corrodes equipment, irritates skin and eyes, and burns through chlorine faster. When it is too high (basic), chlorine becomes less effective and you get cloudy water and scale buildup.

Total Alkalinity: The Stabilizer

Alkalinity acts as a buffer for your pH. When alkalinity is in range, your pH stays stable. When it is too low, pH bounces around unpredictably. Think of alkalinity as the foundation — get it right first, and pH becomes much easier to manage.

Free Chlorine: Your Sanitizer

Chlorine is your primary sanitizer — it kills bacteria, viruses, and algae. "Free chlorine" is the chlorine available to do its job. If it drops below 1 ppm, you are at risk for algae growth and unsafe water.

Calcium Hardness: Surface Protection

Too low and the water becomes corrosive — it will actually pull calcium from your plaster, grout, and equipment. Too high and you get scale deposits on surfaces and inside pipes.

Cyanuric Acid: Sunscreen for Chlorine

CYA shields your chlorine from UV destruction. Without it, sunlight destroys chlorine in hours. Target 30–50 ppm. Too much causes "chlorine lock" where your sanitizer becomes ineffective despite testing as adequate.

When to Call for Help

If your water is persistently cloudy, green, or irritating despite balanced chemistry, there may be a deeper issue — a failing filter, circulation problem, or contamination source. That is when a conversation with our team can save you time, money, and frustration.