Pool Shock - Chlorine or Non-Chlorine

What's
​the Difference?

​Shock. Shock treat. Shock treatment. Each of these terms means the addition of chlorine to pool water in larger than normal amounts. Shock treating your pool is of the utmost importance because it protects you and your family from bacteria and organic contaminants.

What kind of shock should I use? There are three types of shock, Chlorine Shock, Non-Chlorine Shock, and Multi-Function Oxidizer. We’ll start with Chlorine Shock.

Chlorine Shock

Shock used to be a verb. It was something that you did to a pool. It became a noun when they began packaging a pre-measured amount of granulated chlorine into bags. There are 3 types of chlorine that are commonly used as shock.

• Sodium Hypochlorite (Liquid Chlorine)
• Calcium Hypochlorite (Cal Hypo)
• ​Sodium Dichlor (Dichlor)

Cal Hypo
​Cal Hypo is the least expensive and most effective chlorine-based shock. Cal Hypo will not increase the amount of stabilizer (cyanuric acid) in your pool.
We do not recommend using a shock product that is stabilized (i.e. contains cyanuric acid). It will increase the stabilizer level and can interfere with the effectiveness of the chlorine.

​Dichlor
Though effective, DiChlor is the most expensive chlorine-based shock. DiChlor WILL increase the water’s stabilizer (cyanuric acid) level.
We do not recommend using a shock product that is stabilized (i.e. contains cyanuric acid). It will increase the stabilizer level and can interfere with the effectiveness of the chlorine.
​Though it is fast dissolving, it contains only 55% available chlorine.

​Liquid Chlorine
Yes, liquid chlorine CAN be used to shock your pool! It does NOT increase the water’s stabilizer (cyanuric acid) level.


Pool store chlorine, like HASA Sani-Clor, has 12.5% of available chlorine.

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​When To Use Chlorine Shock

Chlorine shock treatments are typically used in swimming pools to address specific issues or as part of regular pool maintenance. Here are a few situations when you might consider using a chlorine shock:

​
Regular Maintenance:
​Shocking your pool on a regular basis is an essential part of pool maintenance. It helps to remove organic contaminants, kill bacteria, and maintain proper chlorine levels. The frequency of shocking depends on various factors, including pool usage, weather conditions, and the type of chlorine used. As a general guideline, shocking your pool every 1-2 weeks is a good practice.

​Algae Growth:
​If you notice green, black, or mustard-colored algae in your pool, it's an indication of an algae problem. Algae can be stubborn and resistant to regular chlorine levels. In such cases, using a chlorine shock treatment can help kill the algae and restore water clarity.

High Combined Chlorine Levels:
​Combined chlorine, often referred to as chloramines, forms when chlorine combines with ammonia or nitrogen-based compounds present in the water. High combined chlorine levels can lead to unpleasant odors, eye irritation, and poor water quality. A shock treatment can break down the chloramines and restore the effectiveness of free chlorine.

Heavy Pool Usage:
​Pools that experience heavy usage, such as pool parties or increased swimmer load, are more prone to contamination. If you've had a particularly busy period with a large number of swimmers, using chlorine shock afterward can oxidize and eliminate contaminants.

How to Use Chlorine Shock
Before shocking your pool with a chlorine shock, the pool water pH MUST BE 7.6 OR LESS. When added to water that has an elevated pH level, chlorine converts to a very inefficient form. To find out more, click the button below.

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LEARN MORE

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Non-Chlorine Shock • Hybrid Shock
When & How to use it

Why use Non-Chlorine shock?
It's a sweltering Saturday afternoon and you've spent your morning doing yard work. Meanwhile, the kids have been running around with their swim fins and arm floaties, loudly voicing their discomfort with the heat.

AT LAST! IT’S POOL TIME! But first, a quick water test. That's when you discover that your afternoon plans have been postponed.

The free chlorine is 10 ppm. Too high. 

Because you used chlorine-based shock that morning, the pool is unusable. The kids are inconsolable and are plotting your demise.
If you had used Non-Chlorine Shock, you could have avoided sitting on the couch and arguing with the dog over the last slice of cold pizza while watching Sponge Bob with the kids.

Non-Chlorine Shock
Containing zero chlorine, non-chlorine shock is also known as “oxidizer”. Its main ingredient is potassium monopersulfate (MPS).
It breaks down soluble organic contaminants in the pool water. These contaminants include sweat, body oils, beauty products, and other matter that may come off or, um, out of the human body. MPS is ideal for weekly, in-season maintenance. Safe for use in ALL pools. Swimming can usually resume after 15 minutes of use.

When to Use Non-Chlorine Shock:

Weekly - As part of a weekly maintenance program.
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Corrective Treatment -  Quickly clears cloudy, dull water.

It is an ideal shock when the following conditions exist.

• The Free Chlorine level is not less than 2 ppm.
• ​There are no algae present.

How to Use Non-Chlorine Shock
​To ensure proper usage of non-chlorine shocks, it's important to follow the instructions provided by the manufacturer on the package, as the strength and dissolvability can vary significantly.

HYBRID SHOCK
​A hybrid shock contains 15% chlorine and 85% non-chlorine shock. It can be used in all pools when there are NO algae and the Free Chlorine is not less than 1ppm. Swimming can resume 15 minutes after use

​Shocking a swimming pool is crucial for maintaining a clean and safe swimming environment. Regular shocking helps eliminate harmful contaminants, such as bacteria, algae, and organic debris that accumulate in the pool water over time. It helps to maintain the proper chemical balance in the pool, ensuring optimal water quality for swimmers and prolonging the lifespan of pool equipment. Overall, regular pool shocking is essential to promote a healthy and enjoyable swimming experience.