Shocking Your Pool: Guide to Swimming Pool Shock Treatments What is pool shock? What does pool shock do? Which type of pool shock is right for you? Recommended Brands

Shocking Your Pool: Guide to Swimming Pool Shock Treatments

If you’re new to swimming pool care, you’ve probably heard of pool shock -- but you might not know exactly what it is, or when and why you should use it.

The good news is that shocking your swimming pool is relatively simple. In this article, we’ll review the basics of pool shock and answer some commonly asked questions about the not-so-shocking world of pool shock.

What is pool shock?

You might be surprised to learn that pool shock is really just an ultra-high dose of pool sanitizer. You can buy pool shock at any pool supply store, and you can choose between a chlorine or a non-chlorine treatment.

What does pool shock do?

Adding pool shock to your pool is kind of like power-washing your swimming pool water. By adding higher-than-normal dose of pool sanitizer to your pool water, you’re effectively killing algae, bacteria, and other contaminants -- and making sure they can’t come back to affect your water quality.

Keep in mind, of course, that pool shock isn’t meant as a replacement for routine swimming pool maintenance: It’s just an extra-powerful addition that can help keep your pool clean and healthy.

For a complete maintenance guide on how and why to shock your pool, click here.

Which type of pool shock is right for you?

There are three basic types of shock treatments available for your pool. The type of shock treatment that you choose will depend on a few factors, including your budget, water chemistry and how quickly you want to swim after you shock your pool.

  • Calcium hypochloride - or “cal hypo,” as the pros say, is a super-concentrated form of chlorine that’s sold in granule or tablet form, and you need to pre-dissolve it before adding it to your pool. It’s super-affordable -- and super-effective at killing algae and harmful bacteria. It’s also super-flammable, which means you need to be careful when handling and storing it. Cal hypo is also quick to burn away in direct sunlight, which means it’s most effective when used at night.
  • Dichloroisocyanuric acid, also known as “dichlor,” is a formulation of chlorine and cyanuric acid. It’s a bit pricier than cal hypo, but unlike cal hypo, it doesn’t need to be pre-dissolved and it’s sun-sensitive, which means you can shock your pool any time.

    You’ll still need to handle it carefully, though: Dichlor is just as flammable as cal hypo.

  • Potassium peroxymonosulfate. Sometimes shortened to “MPS,” this oxygen-based shock treatment is an excellent choice for odor removal and neutralizing ammonia and other contaminants. If you’ve got algae issues, though, MPS might not be the best fit: It’s much less effective at algae removal than chlorine-based pool shock. It’s also one of the most expensive types of pool shock.

Which pool shock is best? That depends on your budget, your reasons for shocking your pool, and whether you prefer to shock your pool during the day or at night. If you’re not sure which option is the best one for you, talk to your pool professional and ask for a few recommendations.

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