How to Increase Free Chlorine in Your Pool: A Step-by-Step Guide

Are you tired of always seeing your pool with cloudy water or supporting algae growth? Well, you’re not alone. Many homeowners face this relentless issue, and it all boils down to how well you take care of your pool. And when talking about algae or cloudy water, you mustn’t forget free chlorine. It’s the chlorine that effectively kills bacteria, reduces algae growth, and eradicates cloudiness from pool water. It’s important to maintain the ideal levels of free chlorine in water (1-3 ppm).

In this blog, we’ll learn how to increase free chlorine in the pool and some practical tips to maintain it.

What Is Free Chlorine and Why Does It Matter?

Free chlorine is active chlorine that disinfects the pool water and kills bacteria and pathogens. In contrast, combined chlorine is the one that reacts with contaminants like sweat, dirt, or body oils in pool water to form chloramines.

Free chlorine is essential to keeping water clear and safe. Low levels of free chlorine lead to cloudiness in pool water and also pose health risks to individuals. Hence, it’s crucial to maintain the ideal free chlorine range (1-3 ppm).

Signs Your Pool Needs More Free Chlorine

If your pool exhibits the following signs, it means it has low free chlorine levels: 

• Cloudy or green water
• Strong chlorine smell (indicating high chloramines)
• Algae growth
• Skin or eye irritation 

Why Does Free Chlorine Drop?

Free chlorine levels change due to the following reasons: 

1. High Bather Load: The higher the number of swimmers, the more contaminants are introduced into the pool.
2. Sunlight (UV Degradation): Breaks down chlorine, making it crucial to consider for outdoor pools.
3. Heavy Rainfall/Debris: Add contaminants and dilute pool chemicals, reducing chlorine effectiveness.
4. Organic Contaminants: Leaves, dirt, oils, sweat, and pet dander lower pool chlorine levels.
5. Low Cyanuric Acid (CYA): Low cyanuric acid levels fail to protect chlorine from UV degradation.
6. High Cyanuric Acid (CYA): High cyanuric acid levels can "lock up" chlorine, making it less effective.
7. Improper pH: Reduce chlorine’s ability to sanitize the pool properly.
8. Chlorine Demand: When chlorine demand is high due to extreme contamination, the existing chlorine gets overwhelmed.
9. Ineffective Circulation/Filtration: Prevents chlorine from being distributed and contaminants from being removed.

How to Increase Free Chlorine in Your Pool (Step-by-Step)

If your pool has constant cloudy water or algae growth, you need to improve the free chlorine levels. Here’s how to raise free chlorine in a pool.

Step 1: Test Your Pool Water

The first step is always to test your pool water. Use a test kit or strips to measure free chlorine and pH levels. To obtain accurate results, collect a water sample from elbow depth, away from skimmers or jets.

Step 2: Assess and Balance pH 

Next, test for water chemistry. pH affects the effectiveness of chlorine, with high pH (above 7.8) reducing its effectiveness and low pH (below 7.2) causing irritation or equipment damage. You should balance the water pH by adding a pH increaser or decreaser, respectively.

Step 3: Choose and Add the Right Chlorine Product

There are various options available to increase free chlorine in the pool. The most commonly available ones are:

• Liquid Chlorine: Fast-acting, ideal for quick boosts, but requires careful handling.
• Granular Chlorine (calcium hypochlorite): Dissolves quickly, suitable for shocking.
• Chlorine Tablets (trichlor): Slow-release, best for ongoing pool maintenance via a floater or skimmer.

First, calculate your pool’s volume (in gallons) to determine the correct chlorine dose. For example, 1 pound of granular chlorine per 10,000 gallons raises the free chlorine level by ~1 part per million (ppm).

You should add chlorine in the evening to minimize UV degradation. Always follow the product instructions for safe handling, including wearing gloves and avoiding inhaling fumes.

Step 4: Run the Pool Filter 

Run the pool filter. Filtration helps distribute chlorine and remove contaminants. Run the pump for 8-12 hours after adding chlorine.

Step 5: Retest and Monitor 

Retest after 4-6 hours to ensure free chlorine is in the 1-3 ppm range. Do not over-chlorinate the pool, i.e., above five ppm, as it can cause skin irritation.

Common Mistakes to Avoid When Increasing Free Chlorine

When adding free chlorine, please avoid the following mistakes.

• Over-chlorinating can harm swimmers and pool equipment.
• Ignoring pH or cyanuric acid levels (high cyanuric acid reduces chlorine effectiveness).
• Failing to clean the pool filter can hinder chlorine distribution.

Preventive Tips to Maintain Free Chlorine Levels 

Here are some effective tips to maintain the ideal free chlorine levels in your pool.

• Regularly test and follow proper maintenance schedules.
• Use a pool cover to reduce debris and UV degradation of chlorine.
• Manage cyanuric acid (30-50 ppm) to stabilize chlorine.
• Shock the pool weekly or after heavy use (e.g., pool parties).
• Frequently vacuum the pool with your pool cleaner to prevent changes in pool chemistry.

Conclusion 

Free chlorine is crucial for maintaining a sparkling clean and sanitized pool. If cloudy water or stubborn algae growth is the problem, free chlorine is the solution. You can easily add free chlorine by first testing the pool water, balancing water chemistry, adding free chlorine, running the pool filter, and then retesting to monitor the levels.

Test your pool today and keep it safe!