calcs.homes
calcs.homes
Enter your pool volume and pick how bad the problem is — regular maintenance, a green pool, or heavy algae — to get the shock dose.
Estimate only — shock at dusk or night, and don't swim until chlorine drops back under 5 ppm.
We divide pool volume by 10,000 gallons and multiply by a base dose of 1 lb of cal-hypo shock (65-73% available chlorine) for routine maintenance, then scale that by your selected level — 1× for routine upkeep, 2× for a green or algae-affected pool, 3× for heavy black algae. Bag counts round up to the nearest 1 lb bag, or 0.5 kg bag in metric.
The 1 lb per 10,000 gallon baseline is the standard maintenance dose printed on most cal-hypo shock labels, sized to burn off chloramines and organic waste without overshooting chlorine levels. Doubling or tripling it for algae follows the same industry convention pool professionals use, since living algae consumes chlorine far faster than normal bather waste and needs a sustained high dose to fully kill off.
Weekly during swim season is typical for routine maintenance, plus after heavy bather load, a storm, or any time the water looks cloudy or green.
Wait until free chlorine drops back to 1-5 ppm, usually 8-24 hours depending on dose and sunlight — test before getting back in.