A shock dose oxidises sweat, chloramines and organic contamination left after normal sanitising. Weekly treatment supports clear, fresh, low-odour water when bathing demand is high.
Two shock products with different jobs: MPS for routine weekly oxidising, calcium hypochlorite for bringing neglected water back.
| What matters | Non-chlorine shock (MPS) | Chlorine shock (calcium hypochlorite) |
|---|---|---|
| Typical use | Routine weekly oxidising after ordinary bathing loads | Resetting water that has turned cloudy or green |
| Mode of action | Oxidises organic bather waste, leaving the sanitiser free to disinfect | Lifts free chlorine to a high level that destroys bacteria and algae directly |
| Effect on the sanitiser residual | Chlorine-free; in bromine systems it regenerates bromide back into active bromine | Adds a heavy chlorine dose above the normal maintained level |
| Wait before bathing | Brief: circulate, retest, then bathe | Until free chlorine has dropped below 5 ppm |
| Frequency | Every week, plus after parties or heavy use | Only when the water needs recovering |
| Cost per treatment | Small regular dose, low cost | Larger dose, but needed far less often |