What Is Calcium Hypochlorite?
Calcium hypochlorite (Ca(ClO)₂) is a popular and powerful chlorine compound used for disinfecting swimming pool water. It usually comes as granules or tablets with high available chlorine content (typically around 65–73%).
⚙️ Why Use Calcium Hypochlorite in Pools?
- Strong oxidizer: Quickly kills bacteria, viruses, algae, and other contaminants.
- High chlorine concentration: Effective at small dosages.
- Fast-dissolving granules ideal for shock treatments (superchlorination).
- Stabilizer-free: Doesn’t add cyanuric acid (unlike trichlor), so you can better control pool chemistry.
- Cost-effective for large pools and commercial applications.
💧 How to Use Calcium Hypochlorite in Swimming Pools
- Shocking the pool: Add 1 lb of calcium hypochlorite per 10,000 gallons of pool water to raise free chlorine by about 10 ppm.
- Regular maintenance: Usually combined with stabilized chlorine tablets for daily sanitation.
- Dissolve granules in a bucket of water before adding to the pool to avoid direct contact with pool surfaces.
- Maintain free chlorine level between 1–3 ppm for safe swimming.
⚠️ Safety and Handling
- Corrosive and reactive: Handle with gloves and eye protection.
- Do not mix with acids or other chemicals.
- Store in a cool, dry, well-ventilated place away from combustible materials.
- Avoid inhaling dust or fumes.
🌡️ Advantages Over Other Chlorine Forms
| Feature | Calcium Hypochlorite | Trichlor Tablets | Sodium Hypochlorite (Liquid) |
|---|---|---|---|
| Available Chlorine (%) | 65–73 | ~90 (stabilized) | ~10–12 |
| Stabilizer Present? | No | Yes (cyanuric acid) | No |
| pH Effect | Raises pH (alkaline) | Lowers pH (acidic) | Raises pH (alkaline) |
| Typical Use | Shocking, bulk dosing | Daily chlorination | Everyday chlorination |
| Storage Stability | High (dry granules) | Moderate (tablets) | Low (liquid degrades fast) |