Pool Chlorination Calculator
Use this calculator to determine the appropriate amount of chlorine product needed to reach your desired free chlorine level in your swimming pool.
Liquid Chlorine (10% Sodium Hypochlorite)
Liquid Chlorine (12.5% Sodium Hypochlorite)
Dichlor (62% Sodium Dichloro-s-triazinetrione)
Cal-Hypo (65% Calcium Hypochlorite)
Trichlor (90% Trichloro-s-triazinetrione)
Understanding Pool Chlorination
Maintaining proper chlorine levels is paramount for a healthy and safe swimming pool. Chlorine acts as a sanitizer, killing bacteria, viruses, and algae, and oxidizing organic contaminants introduced by swimmers and the environment. Without adequate chlorination, your pool can quickly become a breeding ground for pathogens and turn cloudy or green.
What is Free Chlorine (FC)?
Free Chlorine (FC) is the active form of chlorine in your pool water that is available to sanitize and oxidize. It's the chlorine that's doing the work. When chlorine combines with contaminants, it forms "combined chlorine" (chloramines), which are less effective sanitizers and can cause strong chlorine odors and eye irritation. The goal is to maintain a sufficient level of FC.
Ideal Free Chlorine Levels
For most residential pools, the ideal Free Chlorine level is between 1.0 and 3.0 parts per million (ppm). Some experts recommend up to 4.0 ppm, especially during heavy use or hot weather. It's crucial to regularly test your pool water to monitor FC levels and adjust them as needed.
Types of Chlorine Products
Different chlorine products have varying concentrations and properties, impacting how much you need to add and how they affect your pool chemistry:
- Liquid Chlorine (Sodium Hypochlorite): Typically available in 10% or 12.5% concentrations. It's fast-acting, adds no calcium or cyanuric acid, but can raise pH. It's a good choice for shocking.
- Dichlor (Sodium Dichloro-s-triazinetrione): A granular, stabilized chlorine (contains cyanuric acid). It's pH neutral and dissolves quickly. Good for regular chlorination and shocking, but contributes to CYA levels.
- Cal-Hypo (Calcium Hypochlorite): A granular, unstabilized chlorine, usually 65% or 70% concentration. It's effective for shocking and regular chlorination, but adds calcium to the water, which can increase hardness.
- Trichlor (Trichloro-s-triazinetrione): Typically found in tablets or sticks (90% concentration). It's stabilized and acidic, helping to lower pH. Primarily used in feeders for continuous chlorination, not ideal for direct shocking due to slow dissolution and high acidity.
How to Use the Calculator
- Measure Pool Volume: Accurately determine your pool's volume in gallons. If you don't know it, you can often find it in your pool's documentation or estimate it based on its dimensions.
- Test Current FC: Use a reliable test kit or strips to measure your pool's current Free Chlorine level in ppm.
- Set Target FC: Decide on your desired Free Chlorine level (e.g., 3.0 ppm).
- Select Chlorine Product: Choose the type of chlorine product you plan to use from the dropdown menu.
- Calculate: Click the "Calculate Chlorine Needed" button to get the recommended amount.
Important Safety Precautions
- Always read and follow the manufacturer's instructions on your chlorine product.
- Never mix different types of chlorine products, as this can cause dangerous reactions.
- Add chemicals to water, never water to chemicals, especially with granular products.
- Wear appropriate safety gear, including gloves and eye protection.
- Store chemicals in a cool, dry, well-ventilated area, away from children and pets.
- Add chlorine to the pool gradually, especially granular products, to avoid concentrated areas.