DIY: Shocking Your Pool

How to Shock a Pool

Shocking your pool is a great way to bring things back into balance. You’ll enjoy the pleasures of swimming in crystal clear pool water by regularly maintaining and shocking your pool. Shocking your pool breaks up combined chlorine (chlorine + contaminants).

Understanding Chlorine

When testing your pool’s chlorine level, it is important to first understand how chlorine is classified.

  • Free Chlorine: The desirable chlorine available to sanitize or disinfect the water.
  • Combined Chlorine: Undesirable, bad-smelling chloramines that form when not enough free chlorine is present to overcome the chlorine demand.
  • Total Chlorine: The total amount which includes both free and combined chlorine.

How Shocking your Pool Works

  1. Contaminants can get into pools and combine with chlorine. If the free chlorine level is not concentrated enough, it can cause the contaminant to become inert without fully removing it.
  2. Combined chlorine (or chloramines) are ineffective in breaking down harmful bacteria and undesirable organisms. Shocking a pool elevates the free chlorine level to 5-10 ppm.
  3. Elevated levels of free chlorine break up combined chlorine.
  4. Once your pool has been shocked, the water will be clean, clear, and safe for your family to enjoy.

Shocking your Pool FAQ

When is it time to shock your pool?
  • Every couple of weeks during the swimming season.
  • When your pool is outside of the recommended free chlorine levels of 1-3 ppm. Shocking your pool will raise the chlorine level.
What about a salt pool?

Yes, even salt pools need a little help once in a while. Salt water pools utilize a chlorine generator to convert salt into chlorine. You can adjust the generator to increase the level of chlorine produced to counteract higher chlorine demands caused by contaminants. However, even salt water pools need to be shocked when the generator cannot keep up with a heavy load of contamination.

When should you shock your pool?

Regular pool maintenance is essential for healthy, efficient, and economical pool operation. For best results, experts recommend shocking your pool when these circumstances occur:

  • Sun Down – You’ll want to shock your pool in the evening when the sun has gone down. This gives your pool plenty of time during the night to free the chlorine and clean the water. In the morning, you should be able to enjoy your pool. If you shock your pool during the day, the sun’s UV rays will dissolve the chlorine.
  • Opening Day – Before the kids jump in for the new season, you should clean and shock your pool. Over the winter or during times of disuse, algae have a tendency to grow. Make sure the pool water is clean, clear, and healthy for your family before opening day.
  • Party! – The big annual neighborhood pool party will take its toll on your pool water. All those active bodies carry bacteria and the pool’s chlorine has a hard time keeping up. Free chlorine levels drop dramatically after times of heavy use, so bring it back up to normal levels by shocking your pool.
  • Stormy Weather – Spring and summer bring periods of high winds and heavy rains. Combat the changes in your pool water by cleaning your pool and adding shock. This will remove contaminants and bring the pH levels up. You’ll want to reduce the water level to normal before adding shock.
  • Sunny Days– Summer brings the perfect pool weather! But when the days are hot and sunny for long periods of time, the pool water chemistry can be affected. Your pool’s chlorine will combine with contaminants and bacteria and other dangerous organisms will grow as temperatures rise. Bring your water chemistry back into balance. Shock your pool to break up the combined chlorine and release it back to free chlorine.
  • Closing Time – Nobody likes it, but at some point, most pool owners will say “Adios!” to pool season. When the time comes, think ahead by cleaning and shocking your pool. You’ll be glad you did it! Next year, when the new pool season comes, you’ll have a head-start on opening your pool.
How do I shock my pool?

Shocking your pool is a fairly simple process. Before you begin, uncover your pool, skim the pool, vacuum the sediment, and brush the walls, floor and coves. Before adding shock, you’ll want to protect yourself with the appropriate gear; which includes protective goggles, gloves, and work clothes.

  • Check that the pH levels in your pool are balanced
  • Prepare shock ahead of time in a 5-gallon bucket of pool water and stir.
  • Ensure the pool pump is running. Pour the mixture from the bucket into the water around the edges of the pool.
  • Let the pump run for about 6 hours or more and test the water. Don’t use the pool right away – wait for the free chlorine levels to drop to 1 – 3 ppm before it is safe to swim.

When water tests okay, you are ready to go – dive right in!