Pool Shock Dose
Calculator
Results
- Active chlorine needed (g)
- 500
- Product to add (g)
- 714.285714
- Product to add (kg)
- 0.714285
- Water volume (m³)
- 50
Pool and aquarium results
| Active chlorine needed (g) | 500 |
| Product to add (g) | 714.285714 |
| Product to add (kg) | 0.714285 |
| Water volume (m³) | 50 |
formula-map diagram
- Active chlorine needed (g)
- 500
- Product to add (g)
- 714.285714
- Product to add (kg)
- 0.714285
- Water volume (m³)
- 50
Pool and aquarium relationship
Formula
shock = raise(ppm) × volume(m³) ÷ (strength ÷ 100)= 500
Note
This is a simplified model: it applies a standard geometric or physical formula to the numbers you entered. Volumes assume a regular shape and an even average depth, and the kidney shape uses the common 0.45 × (A + B) × L area approximation. Chemical doses convert a target change into a product mass using the strength or label dose you enter, because the amount of active ingredient varies from product to product; they ignore pH, temperature, buffering, sunlight, bather load and existing chemical interactions. Heating uses Q = m × c × ΔT with c = 4186 J/kg·K and ignores heat losses to air, ground and evaporation; evaporation and cover figures use the rate you enter, not local weather. Aquarium stocking by surface area is a rule of thumb, not a biological limit. Always follow the product label and test the water before and after dosing, and consult a pool or aquarium professional for anything you are unsure about.
More in Pool and aquarium
See all →Frequently asked questions
What does 'shocking' a pool actually do, and how is the dose different from regular chlorine dosing?+
Shocking means raising free chlorine to 5-10x the combined chlorine level (a process called breakpoint chlorination) to destroy chloramines, algae, and bacteria all at once, rather than the small daily maintenance dose used for routine sanitizing. The calculator uses your pool volume and current combined chlorine or general condition (algae, heavy bather load) to estimate that much larger one-time dose.
Why does the calculator ask about combined chlorine or 'why do I need to shock' rather than just target a fixed ppm?+
The breakpoint chlorination target scales with how much combined chlorine (chloramine) is already present — the rule of thumb is roughly 10 times the combined chlorine reading. Without knowing that starting point, a fixed generic dose could be far too small to actually reach breakpoint, leaving the pool smelling of chlorine but still under-sanitized.
Why does my pool smell strongly of chlorine right after shocking, even though pH and chlorine levels seem fine the next day?+
That smell comes from chloramines, not from too much chlorine — it's precisely what shocking is meant to eliminate, but the odor may briefly increase as chloramines break down before the reaction completes. Chlorine off-gasses within 24-48 hours as it converts to harmless nitrogen and chloride.
Is it safe to swim right after shocking a pool?+
No — most shock treatments push free chlorine well above the safe swimming range (over 5 ppm), and you should wait until the level naturally drops back into the 1-3 ppm range, usually 8-24 hours depending on dose size and sunlight. Test before swimming rather than relying on a fixed wait time.
Why would I need a bigger shock dose for algae than for routine chlorine maintenance?+
Algae blooms have a much higher chlorine demand because the organism itself, along with the organic material it produces, consumes chlorine rapidly; a standard maintenance dose gets consumed before it can build a sanitizing residual. A double or triple shock dose (per label instructions) overwhelms that demand so free chlorine can actually accumulate and kill the algae.