How to Shock Your Above Ground Swimming Pool

What is a Pool Shock?

Shocking your above ground pool is a necessary part of its maintenance routine. A “shock” simply refers to adding above normal levels of chlorine or sanitizer to your pool to quickly raise the levels of chemicals in a very short amount of time.

The reason for shocking a pool is to remove ineffective chlorine, kill bacteria, and get rid of algae. Additionally, you’ll be raising the level of effective chlorine and helping your pool get clean and safe to swim in again.

What you’ll need to shock your above ground pool:

  • Water chemical test kit.
  • Pool cleaning supplies (brush, skimmer, vacuum, etc.)
  • Pool shock mix/shock kit
  • Bucket for mixing.
  • Water.

How to Shock Your Above Ground Pool

If you’ve got algae growth in your pool, the water smells weird, or your test kit is reading abnormal levels, you’ll need to shock your pool.

  • Clean your pool thoroughly BEFORE applying the shock treatment.
  • Wait until the sun goes down to start the shock. The sun lowers the effectiveness of the shock chlorine.
  • In a bucket, mix your pool shock chemicals into water from the pool until they dissolve.
  • Run your pump and filter constantly while you’re shocking your pool.
  • Pour the mixed and dissolved pool shock evenly around your pool or slowly in front of one of the inlet jets from your pool’s pump.
  • Wait at least an hour after the shock and test the chlorine levels.
  • The pool will be safe to swim in again after chlorine levels return to normal. Different shock mixes may take different amounts of time until the chemicals return to normal levels.

Cleaning your above ground pool before the shock 

In order to apply a pool shock to its maximum effectiveness, you’ll need to make sure your above ground pool is completely clean. Run your vacuum as you brush the sides and skim the top of the water. Chlorine works to neutralize organic matter and bacteria – the more you can remove before hand, the more effective the shock will be on the stuff you can’t see – like algae, skin cells, oils, etc. Nasty, I know!

Types of Pool Shock

The main types of pool shock chemicals are:

  1. Cal-hypo.
  2. Sodium di-chlor.
  3. Potassium monopersulfate.

Cal-hypo is the strongest pool shock available. It’s quick dissolving, but should be pre-dissolved in a bucket before being added to the pool. Failing to pre-dissolve the pool shock can lead to liner bleaching or pin holes in the worst case scenario. The sun will eat it up pretty quickly, so it’s best to use cal-hypo pool shock at night. This type of pool shock is best if the water has already turned green. After shocking a pool with cal-hypo, you can swim again once the chlorine levels have returned to normal.

Sodium di-chlor is a slow dissolving pool shock that increases the cyanuric acid levels in your pool. Di-chlor should be added when the sun goes down. You can swim again once chlorine levels have returned to normal.

Potassium monopersulfate is oxygen based and doesn’t contain chlorine. It helps to remove water contaminants by oxidizing the water and helping the chlorine already in the pool to work better. You’ll be able to swim after about 15 minutes of using this type of pool shock. If bromine is used as your primary sanitizer/conditioner, this is the best type of pool shock for your pool.

You can use any one of the 3 main types of pool shock for regular shock maintenance.

When to Shock Your Above Ground Pool

How often you’ll need to shock your pool will really vary depending on use, climate, and how diligent you are about maintenance.

The most common times you’ll need to shock you pool include:

  • If you notice algae growth.
  • After heavy rainfall.
  • After constant hot weather.
  • As part of your pool opening routine.
  • After heavy use of the pool.

If you haven’t noticed already, a few of those bullet points are pretty standard to summer weather in most places. Depending on your location and pool usage, you may find that you’ll need to shock your pool anywhere from once a week to monthly.

If you’re keeping a regular cleaning and maintenance rhythm for your above ground pool, you should be testing your water chemistry at least once per week. Your effective chlorine levels will tell you when exactly you need to shock your pool.

You’ll definitely need to shock your pool and use some algaecide if your above ground pool’s water starts to turn green or give off a foul oder.

While shocking your pool is part of its regular maintenance, you can do your part to minimize the need to shock it by:

  • Regularly brushing the walls and running the vacuum.
  • Keeping a cover on the pool when its not in use.
  • Encourage swimmers to rinse off before entering the pool.
  • Regularly testing and adjusting water chemistry and chlorine levels.
  • Running the filter system often.
  • Cleaning the ladder, pool equipments, and taking pools floats and toys out of the pool when they’re not being used.
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