Leisure Time RENU2 Renew Non-Chlorine Shock Treatment, 2.2 lbs

Shocking means adding an oxidizer that breaks down what soakers leave in the water – sweat, body oils, soap and deodorant residue. Renew does it without chlorine: the active ingredient is potassium peroxymonosulfate, in granules the maker describes as quick dissolving and buffered against pH swings. The maker says it clears cloudy water and removes odors, and lists it for weekly use.

The important line on the listing is a short one: not a disinfectant. It works next to chlorine or bromine and never in their place. The label carries a “Danger – Corrosive” warning, and the listing gives no dose, so the label on the bottle is the instruction to follow.

Tip: Dose with the pump running and the cover open, then leave the cover open for about 20 minutes. Add the granules to the water – never water to the granules – and never mix them with any other chemical.