If there is a strong smell of chlorine coming from your pool then there is most likely in need of an oxidising (or) shock treatment. A shock treatment should be done at least monthly. The odour of strong chlorine occurs when the chlorine in your pool has combined with the organic matter and bather wastes within the pool. This combined chlorine remains in the pool however it is unhealthy and is no longer free and available to continue its action as an effective sanitiser. Oxidising pool water in a regular pool maintenance routine is often overlooked but it is one of the most important steps in keeping your pool healthy for swimming and running properly.