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Sold by: Pool Supply World
Sold by: Pool Supply World
(44589 ratings)
89% positive over last 12 months
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In The Swim Pool Shock – 68% Cal-Hypo Granular Sanitizer for Crystal Clear Water – Defends Against Bacteria, Algae, and Microorganisms - 12 X 1 Pound

4.6 4.6 out of 5 stars 13,616 ratings
Amazon's Choice highlights highly rated, well-priced products available to ship immediately.
Amazon's Choice in Swimming Pool Chlorine by In The Swim

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Bag
12 x 1 Pound

Purchase options and add-ons

Brand In The Swim
Item Weight 13.07 Pounds
Item Form Granular
Product Benefits Contaminants

About this item

  • Powerful chlorine shock treatment that is great for regular maintenance.
  • Quickly eliminates algae, bacteria, and other harmful contaminants from your pool water.
  • Main active ingredient is 68% Calcium Hypochlorite (Cal-Hypo) for quick sanitizing.
  • Dosage: 1 Pound per 10,000 gallons
  • Cal-Chlor granules can be used in swimming pools, spas and hot tubs. Must pre-dissolve/dilute to prevent bleaching of the liner.

Customer ratings by feature

Easy to use
4.6 4.6
Longevity
4.5 4.5
Sheerness
4.5 4.5
Accuracy
4.5 4.5

Frequently bought together

$69.99 ($0.36/Ounce)
In Stock
Ships from and sold by In The Swim Pool Supplies.
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$14.88 ($0.12/Fl Oz)
Get it as soon as Tuesday, Apr 2
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Ships from and sold by Amazon.com.
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Product Description

ITS Chemical Lineup

In The Swim Calcium Hypochlorite Pool Shock

Swimming pool shock treatments are an essential aspect of spring pool opening, but can also be used to give your pool a quick chlorine boost. Our most popular and versatile pool shock treatment, used to kill algae and bacteria that make pool water cloudy. Use our Pool Shock to kill visible algae blooms and invisible bacteria, which could cause illness to swimmers. Daily chlorination of the pool will kill most pathogenic bacteria, viruses, and microbes.

Cal-Hypo main image
Cal-Hypo features
Cal-Hypo benefits
Cal-Hypo directions
Cal-Hypo pro tip

Choose Your Chemical

Cal-Hypo main image

Cal-Hypo Pool Shock

3 inch tabs 50 lb bucket

3 Inch Chlorine Tablets

Bromine 50lb bucket

Bromine Tabs

Multi Tabs 50lb bucket

5-in-1 Super Multi-Tabs

Di-Zap

Di-Zap 3-in-1 Shock

Customer Reviews
4.6 out of 5 stars
13,616
4.6 out of 5 stars
18,429
4.7 out of 5 stars
2,511
4.6 out of 5 stars
625
4.6 out of 5 stars
104
Purpose
Chlorinating Water Sanitizing Sanitizing Sanitizing Sanitizing
Main Ingredient
Calcium Hypochlorite Trichloro Bromine Trichlor Dichlor
Ingredient %
68% 99% 61% 84% 99%
Application
Pre-dissolve Floating dispenser Floating dispenser Floating dispenser Floating dispenser
Key Features
Versatile fact-acting shock Long lasting defense Odorless Multi-Functional Incl. Algaecide & Stabilizer

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In The Swim Pool Shock – 68% Cal-Hypo Granular Sanitizer for Crystal Clear Water – Defends Against Bacteria, Algae, and Microorganisms - 12 X 1 Pound


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This Item
In The Swim Pool Shock – 68% Cal-Hypo Granular Sanitizer for Crystal Clear Water – Defends Against Bacteria, Algae, and Microorganisms - 12 X 1 Pound
In The Swim Pool Shock – 68% Cal-Hypo Granular Sanitizer for Crystal Clear Water – Defends Against Bacteria, Algae, and Microorganisms - 12 X 1 Pound
Recommendations
In The Swim Di-Zap Multi-Shock 24 x 1 lb. Bags
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In The Swim Di-Zap Multi-Shock 12 x 1 lb. Bags
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CLOROX® POOL&SPA™ Shock XTRABLUE®2-12pk
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Price-7% $69.99
List:$74.99
-6% $187.99
List:$199.99
-14% $49.05
Typical:$56.79
-5% $115.99
List:$122.47
-37% $27.03
List:$43.00
-22% $54.67
List:$69.99
Delivery
Get it as soon as Tuesday, Apr 2
Customer Ratings
Easy to use
4.6
4.9
4.6
4.9
4.7
4.6
Value for money
4.3
4.4
4.1
4.4
4.3
4.1
Maneuverability
3.7
5.0
5.0
4.2
4.8
Longevity
4.5
4.2
4.2
Sold By
In The Swim Pool Supplies
In The Swim Pool Supplies
Amazon.com
In The Swim Pool Supplies
Amazon.com
Amazon.com
form
Granular
Powder
Tablet
weight
13.07 pounds
25.43 pounds
1 pounds
12.93 pounds
13.3 ounces
12 pounds

Customer reviews

4.6 out of 5 stars
4.6 out of 5
13,616 global ratings

Customers say

Customers like the quality and value of the pool spa water treatment. For example, they mention it works well, and is easy to use. Some are happy with the chlorine level, dissolves, clarity, and cleanliness. That said, opinions are mixed on the level of chlorine and the product's effectiveness.

AI-generated from the text of customer reviews

731 customers mention642 positive89 negative

Customers like the quality of the pool spa water treatment. They mention it works fantastic, is consistently reliable, and effective. The product is great and competitively priced. It helps to reduce bad bacteria and destroys a variety of disease-causing organisms.

"This chlorine shock works well. It comes in 1lb plastic bags that are easy to handle and will not break open on accident...." Read more

"...this does not make the water taste salty, is easy to store, is stable, adds hardness, is cheaper source of Chlorine, does NOT add CYA!..." Read more

"Product is great and competitively priced...." Read more

"This is the second time I have purchased this product and it really works! The first time I purchased it my pool was green!..." Read more

434 customers mention398 positive36 negative

Customers are satisfied with the value of the pool spa water treatment. They mention that it is worth every penny, and has saved them money in the long run. They also say that it's the cheapest way to add chlorine to your pool, and that it saves them gas from having to go get it.

"...back to normal, I at first wasn't sure because of the price, its worth every penny and I liked how fast it arrived." Read more

"...paying shipping expenses (have Amazon Prime), this is the cheapest way to add chlorine to your pool, AND it adds calcium, AND you are not raising..." Read more

"...] Product is great and competitively priced...." Read more

"...In the long run, it has saved me money...." Read more

141 customers mention137 positive4 negative

Customers find the pool spa water treatment easy to use. They mention it's convenient, simple, and quick to use, with clear instructions. Some say it works better and easier than liquid chlorine, and is a fraction of the price of other brands. Customers also say it'll keep their pool algae-free, and that it'd be easy to walk around the pool and spread the contents.

"...It comes in 1lb plastic bags that are easy to handle and will not break open on accident...." Read more

"...does not make the water taste salty, is easy to store, is stable, adds hardness, is cheaper source of Chlorine, does NOT add CYA!..." Read more

"...Easy to use and sprinkle throughout the pool and spa area...." Read more

"Easy to use, appears to work well. Just ordered a second." Read more

129 customers mention90 positive39 negative

Customers are mixed about the cleanliness of the pool spa water treatment. Some mention that it clears their pool up much better than other brands, while others say that it makes their pool liner extremely slimy.

"...this once a month along with the same brand chlorine tabs and my pool looks great! Easy to use and sprinkle throughout the pool and spa area...." Read more

"...The algae spots were gone and the pool water is clear and looks great...." Read more

"...does when broadcasting in pool and sinks to bottom and needs to be brushed to spread out...." Read more

"...Calcium hypochlorite is one of the best chemical disinfectants for water, better than household bleach by far...." Read more

87 customers mention73 positive14 negative

Customers like the shock. They mention it's a super product, does the job, and comes quickly. Customers also say that it naturally dissolves and hasn't had any issues. They say it'll be perfect for your pool and is a high quality shock treatment for a reasonable price.

"This is great pool shock!" Read more

"...Best prices usually here at Amazon for pool supplies. Very effective shock. Keeps the water crystal clear." Read more

"Perfect shock for the AZ sun… keeps mustard algae away … I use one a week for the summer to keep the chlorine high in the summer sun!!" Read more

"Great shock. Keeps pool sparkling clear. The individual packs are so convenient. No measuring or mess. Will purchase again." Read more

129 customers mention70 positive59 negative

Customers are mixed about the clarity of the pool spa water treatment. Some mention that it makes their pool crystal clear every time, while others say that it made the water cloudy for several days.

"...Very effective shock. Keeps the water crystal clear." Read more

"...OF COURSE the water will go cloudy - it is *Calcium* HypoChlorite, but the cloudiness only lasts a short time...." Read more

"...The algae spots were gone and the pool water is clear and looks great...." Read more

"...It definitely does the job but not as clear or easy as others." Read more

109 customers mention34 positive75 negative

Customers are mixed about the dissolves. Some mention that it dissolves relatively easily, while others say that it takes a while to dissolve. Some say that not all the granules dissolve, and that it never fully dissolves in their salt water pool.

"...It doesn’t dissolve very easily, so I do it in a bucket, then pour any remaining granuals into the skimmer...." Read more

"...Can’t swim in 15 minutes with this product vs AC. ITSwim doesn’t dissolve like AC does when broadcasting in pool and sinks to bottom and needs to..." Read more

"Low cost; dissolves relatively easily..." Read more

"...It never fully dissolved but it was a higher percentage of chlorine than the stuff we get at our local pool store so we thought maybe that’s why...." Read more

58 customers mention32 positive26 negative

Customers are mixed about the chlorine level of the pool spa water treatment. Some mention that it dissolves quickly, brings available chlorine up without any pH increase like liquid chlorine, and that the levels are pretty stable. However, others say that it does not hold the chlorine content for more than 2 days, and the pool was too chlorinated by a lot.

"...at a minimum of 65% cholorine for well over 1 year, it does not go bad like liquid chlorine, which loses 1/2% + concentration per month!..." Read more

"...I've tested my water daily for over a month and it show no chlorine even after using 6 pounds a day for 5 days...." Read more

"...the big name store at a fraction of the price and the active ingredients are almost identical" Read more

"...It never fully dissolved but it was a higher percentage of chlorine than the stuff we get at our local pool store so we thought maybe that’s why...." Read more

Doesn’t desolve
3 Stars
Doesn’t desolve
It mentions on the package that “if” the product doesn’t dissolve at first, just stir up the water. We gave it the benefit of the doubt the first few times we dropped this in, but having to stir a dissolvable powder 3-4 times in a 9ft pool (albeit a very first world problem) is still an inconvenience.Other products we’ve purchased dissolve within minutes but this just sinks straight to the bottom and sits there.I have a feeling that even after we stir it up it still doesn’t dissolve and just gets sucked up into the filter.
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