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Shock Treatment
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shocking spas and hot tubs A large percentage of water problems reported to us by spa owners can easily be corrected by the proper application of shocking compounds. We'll explain the different recommended types, and the right way to use them.

What is Shock Treatment?

Shocking a hot tub spa is the application of an ample dose of chlorine (sodium dichlor) or non-chlorine shock (potassium monopersulfate or MPS). One purpose of this treatment is to break-down organic waste contaminants which cause odor and cloudy water. After treatment, water quality and clarity is often completely restored.

If irritating chloramines are present, shocking also converts them back to active chlorine. If bromine sanitizer is being used, shocking activates the bromide ion (which by itself has no disinfecting capability) which becomes hypobromous acid in water, a good sanitizer. Both of these shocking products are 100% compatible with the alternative sanitizer systems that we offer.

Regardless of which sanitizer system you use, periodic shocking is essential for clear, clean hot tub water. It will also allow your sanitizer to perform at peak efficiency.

Note: These products are not compatiblewith biguanides such as Baqua® which we do not support.

Non-Chlorine Shock - regular use for maintenance

Oxy Spa non-chlorine shock Non-chlorine shock is monopersulfate compound, often called MPS for short. It is an oxygen-based shock, preferred by many because it has little or no odor.

Our OxySpa brand non-chlorine shock is 100% compatible with chlorine, bromine, Cleanwater Blue, Nature2 and Frog products, as well as dichlor shock. It is the ideal primary shock to use with these products on a regular basis. Although not classified as a sanitizer, non-chlorine shock does oxidize contaminants and greatly improves water quality and clarity.

Dichlor Shock - occasional use to clear up problems

Dichlor granular chlorine shock Dichlor shock is a form of chlorine often called sodium dichlor. Technically it's both a sanitizer and a shock, although we do not recommend chlorine as a primary sanitizer in spas.

Dichlor is 100% compatible with bromine, Cleanwater Blue, Nature2 and Frog products, as well as non-chlorine shock.  It is recommended for use as a startup shock with these products, and also for occasional use to correct water problems quickly

Shocking with dichlor (sometimes referred to as superchlorination) is the fastest and easiest way to clear up many water problems such as musty odor, cloudiness, slimy water, algae, etc. Note: dichlor should always be pre-dissolved in a plastic bucket of water prior to addition to spa, to avoid possible damage to acrylic surfaces or vinyl liners.

When to Shock

Couple in their hot tub It is a good practice to shock with dichlor when you refill your spa. After that, regular maintenance can normally be accomplished with non-chlorine shock.

Other times for shock treatment would include: prior to, or just after a party or other period of heavy use, when the spa has been neglected, or when restarting a spa that has not been used for some time. Whenever your regular dosage of non-chlorine shock seems to need an extra boost, dichlor will usually provide it and clear up problems. Read more about the decontamination method for hot tubs with severe, persistent water quality issues.

With Alternative Water Purifiers

Many people have switched to alternative purification systems such as Cleanwater Blue or Nature2 to get away from chlorine. It is still a good idea to start these systems with a dose of dichlor. This ensures a clean start and will help prevent problems from pre-existing contamination, that would otherwise put a high demand on alternative products. Dichlor is also the quickest way to fix problems after a heavy bather load.

Cleanwater Blue alternative purifier

If you don't like chlorine, do not despair. Remember that with the cover open, jets running, or exposure to sunlight, that occasional chlorine dose will dissipate fairly quickly.

With alternative sanitizers, OxySpa non-chlorine shock will be your primary maintenance compound, and in many cases users rarely use dichlor after the startup dose.


The amount of shock to use will depend on the bather load, and which water sanitization system you have chosen. Refer to our Preparation & Maintenance Guide and read all product package directions for more information.

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