Pool Water Chemistry Explained: pH and Chlorine Levels Demystified
The Secret to a Sparkling Pool is Not a Secret at All: It’s Pool Water Chemistry
Every swimming pool owner wants a clear, comfortable, and safe pool. Yet, the moment you look at a water testing kit, you're faced with a confusing array of terms and numbers.
The truth is, keeping your water balanced comes down to two simple, crucial numbers: pH and chlorine level. If these two are off, you'll fight constantly with cloudy water, algae, and eye irritation.
This guide will break down the "Big Two" of pool chemistry so you can finally understand what your water is telling you—and when it’s time to call a professional pool service.
1. pH: The Comfort and Corrosion Factor
The pH level is a measure of how acidic or alkaline (basic) your pool water is. It’s measured on a scale of 0 to 14.
pH Levels
The Ideal Range (The SEO Sweet Spot)
The ideal pool pH level is between 7.4 and 7.6. This range is not arbitrary; it matches the pH of the human eye, which is why a well-balanced pool is comfortable to swim in.
What Happens When Your pH is Too Low (<7.4)?
Low pH means your water is becoming acidic.
Irritation: Causes itchy skin and burning red eyes.
Corrosion: The acidic water eats away at your expensive equipment, leading to corrosion of metal components like heaters, handrails, and pump parts.
Chlorine Burn: Your pool chlorine burns off much faster, meaning you waste money on chemicals that don't last.
What Happens When Your pH is Too High (>7.6)?
High pH means your water is too alkaline.
Cloudy Water: The most visible sign is cloudy pool water or a hazy appearance.
Scale Formation: High pH causes calcium to come out of solution, leading to scaling on the pool walls, tile grout, and inside your filter.
Chlorine Inefficiency: This is the most critical issue: high pH locks out chlorine, rendering it ineffective even if you have a sufficient amount in the water.
2. Chlorine: The Sanitation Superstar
Pool chlorine is the primary sanitizer that kills bacteria, viruses, and algae. However, when checking your levels, you need to understand two key terms:
Free Chlorine (FC)
What it is: The active, working chlorine in your pool, ready to sanitize. This is the number you need to monitor daily.
The Ideal Range: Generally, 2.0 to 4.0 parts per million (ppm).
Combined Chlorine (CC) or Chloramines
What it is: Used-up chlorine that has reacted with swimmer waste (sweat, oils, urine). It’s "combined" with these contaminants and is no longer an effective sanitizer.
The Problem: Combined chlorine is what causes that strong, offensive chlorine smell—it's not a sign of too much chlorine, but of ineffective chlorine!
When to "Shock" Your Pool
When your Free Chlorine is too low, you need to add more.
When your Combined Chlorine is above 0.5 ppm, it's time to perform a pool shock. Shocking the pool is simply adding a large, concentrated dose of chlorine to break apart those ineffective chloramines and re-establish a healthy level of Free Chlorine.
3. The Essential Relationship: pH and Chlorine
You cannot balance one without the other. This is the biggest mistake DIY pool maintenance owners make:
If your pH is too high, you can add all the chlorine in the world and it won't work.
The only way your chlorine can effectively sanitize the water is if the pH is properly balanced in the 7.4 to 7.6 range. They work as a team!
🛑 Ready to Take the Guesswork Out of Pool Chemical Balancing?
Testing and adjusting your swimming pool chemistry is a weekly necessity, and it's easy to get frustrated when the numbers never seem right.
As your local pool care service, we specialize in precision. We use professional-grade testing and commercial-strength chemicals to guarantee a perfect water balance every single time.
Stop fighting the chemical battle and start enjoying your pool.
Call us today to schedule your first weekly maintenance and chemical balancing service: 727-788-0864
