Pool Shock Calculator
Find the right shock dose for your pool size, situation, and product type.
Pool Volume
gallons
Treatment Situation
Shock Product
Shock Needed
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Estimated Cost
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Pool Volume
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Best time to shock: evening or at dusk. Sunlight destroys unstabilized chlorine rapidly. Run the pump for at least 8 hours after shocking, and retest before swimming.
Safety Warnings
- Never mix different shock products or any pool chemicals together — this can cause fire, explosion, or toxic gas.
- Always add shock to water, not water to shock. Pre-dissolve granular shock in a bucket of pool water first.
- Wear gloves and eye protection. Work outdoors or in a well-ventilated area.
- Do not swim until chlorine levels drop below 4 ppm (typically 8–24 hours).
- Store shock in a cool, dry place away from sunlight, heat, and other chemicals.
When and Why to Shock Your Pool
Pool shocking means adding a large dose of chlorine (or non-chlorine oxidizer) to break down chloramines, kill algae, and restore water clarity. The standard rule is 1 lb of granular shock per 10,000 gallons, but certain situations require more.
| Situation | Dose | Notes |
|---|---|---|
| Weekly maintenance | 1 lb / 10k gal | Keeps water clear, prevents algae |
| After heavy use / party | 1.5 lb / 10k gal | Eliminates excess chloramines |
| Green algae | 2 lb / 10k gal | Brush walls first; repeat if needed |
| Pool opening (spring) | 2 lb / 10k gal | After balancing pH and alkalinity |
| Black algae | 3 lb / 10k gal | Scrub vigorously; may need multiple treatments |
Cal-Hypo (calcium hypochlorite) 65% is the most common shock product. It raises calcium hardness slightly. Dichlor 56% adds cyanuric acid (stabilizer) and is pH-neutral. Liquid sodium hypochlorite is effective and leaves no residue, but is less concentrated.