When Should I Use A Pool Shock Treatment?
As a general rule you should super-chlorinate or “shock” your pool on a regular basis (at least weekly or every two weeks during the summer). Many pool users make it a regular routine to shock the pool every Sunday as this coincides with the end of the most active period of use. Regular shocking ensures that levels of chloramines are minimized by reducing the contaminants that lead to their formation (e.g. skin cells, sun cream, leaf little, bird droppings, urea, bacteria and other pathogens). You may also need to do additional pool shock treatments when:
- The free chlorine level has bottomed out or the combined chlorine reading is too high.
- The pool water is not completely clear but has taken on a cloudy, dull or murky appearance. Cloudy water is normally a result of dead algae and bacteria rather than pool chemistry.
- Swimmers complain of a “chlorine-like” odor or haze hanging over the surface of the pool. The smell is a result of chloramines (also known as combined chlorine compounds). Chloramines are also the cause of eye irritation.
- There has been any heavy rainfall. Rain can wash organic contaminants and other debris into the pool.
- There has been an extended period of warm weather and sunshine. High temperature and sun rays speed up the breakdown available chlorine.
- You notice any sign of algae formation.
- There have been periods of heavy bather usage, especially if people have not showered before using the pool.
- There is evidence of a slime on underwater surfaces
When applying a pool shock treatment the goal is to ensure a 1-3 ppm free chlorine (or available chlorine) test reading. You will need to add 10 times the amount of free chlorine as there is combined chlorine in the pool to get rid of. You will need a good quality chlorine kit that is capable of measuring free chlorine levels to ensure that you know that you have reached breakpoint chlorination. You will know you have reached this point when the free chlorine levels start to rise.
When adding the swimming pool shock treatment ensure that the water filtration system is working, that skimmers and filters are clear of any debris and there are no swimmers in the water. If you can, wait until the sun is no longer high in the sky. Broadcast the shock treatment over the deep end of the water and repeat until you reach a stable level of free chlorine.