Is it Time to Shock Your Pool?
It’s possible that a well-maintained pool will rarely need shock treatment. It is sometimes necessary, however. Depending on circumstances, shock treatment can be frequently required, to maintain a healthy swimming environment. See the following answers to common questions about shocking your swimming pool.
What does it mean when you shock a pool?
Shocking a pool is a process of adding chemicals in the pool to raise the “free chlorine” level to a point where algae, bacteria, chloramines, and other contaminates are destroyed. The chemicals added may be chlorine or non-chlorine chemicals.
What is “free chlorine” as opposed to “total chlorine?”
“Total chlorine” or “combined chlorine” levels provide an indication of chlorine that has already combined with pool contaminants to destroy them. “Free chlorine” is the chlorine that is usually tested when proper chlorine levels in a pool are checked. If chlorine levels aren’t at a certain level, it’s not safe to swim, due to the contaminants in the water.
What kinds of pool shock are there and how do they work?
There are two basic kinds of pool shock and they are: chlorine and non-chlorine.
A chlorine shock involves adding chlorine until it is at a high level, to destroy contaminants in the pool. The typical chlorine-based shock raises the level of chlorine to 10 ppm. The potential disadvantage to this method is that there could be a long waiting time before it is safe to swim. It could take a full day or more for the chlorine level to drop down to a safe 3 to 4 ppm level.
A non-chlorine treatment typically involves the use of potassium monopersulfate. While this chemical does a good job of oxidizing contaminants, it does not kill bacteria. This type of pool shock treatment is best when it’s not convenient to delay swimming. Manufacturers of shock products say it’s fine to swim 15 minutes after a non-chlorine shock treatment. Many pool experts, however, recommend waiting until the following day, no matter which type of shock treatment you use.
How can you tell it’s time to shock your pool?
After excessive activity in your pool, you may notice that the water has become murky. Suntan oils and lotions, perspiration, cosmetics, hairspray, and other organic materials react to chlorine to form combined chlorine. Total chlorine is a poor disinfectant, and it can cause skin and eye irritations and form an unpleasant chlorine odor. A cloudy pool is a health risk, and a shock treatment is needed to restore your healthy swim environment with an appropriate level of free chlorine.
Other times when a pool shock is needed:
- Twice per swim season, even if there are no signs a shock is needed.
- In general, how often a pool needs to be shocked depends upon how frequently and how many swimmers use the pool in correlation to such weather conditions as long periods of rain or sun.
- When algae begins to grow in your pool.
- The free chlorine level of your pool measures zero.
- The combined chlorine level in your pool rises above 0.5.
Contact the pool experts at Pool Works for a pool shock or the chemicals needed to shock your pool. A shock is just one more way to keep your swimming pool in top condition.