Search  for anything...
In The Swim

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

    • Based on 13,492 reviews
Condition: New
Checking for product changes
$69.99 Why this price?
Holiday Deal · 7% off was $74.98

Buy Now, Pay Later

As low as $11.67 / mo
  • – 6-month term
  • – No impact on credit
  • – Instant approval decision
  • – Secure and straightforward checkout

Ready to go? Add this product to your cart and select a plan during checkout. Payment plans are offered through our trusted finance partners Klarna, PayTomorrow, Affirm, Afterpay, Apple Pay, and PayPal. No-credit-needed leasing options through Acima may also be available at checkout.

Learn more about financing & leasing here.

Selected Option

Free shipping on this product

This item is eligible for return within 30 days of receipt

To qualify for a full refund, items must be returned in their original, unused condition. If an item is returned in a used, damaged, or materially different state, you may be granted a partial refund.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

Availability: In Stock.
Fulfilled by In The Swim Pool Supplies
Arrives Sunday, Dec 22
Order within 4 hours and 51 minutes
Available payment plans shown during checkout

Style: Bag


Size: 12 x 1 Pound


Features

  • 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.

Brand: In The Swim


Item Weight: 13.07 Pounds


Item Form: Granular


Product Benefits: Contaminants


Product Dimensions: 10.8 x 9.9 x 5.3 inches


Item Weight: 13.07 pounds


Manufacturer: In The Swim Discount Pool Supplies


Item model number: 25235 12X1


Is Discontinued By Manufacturer: No


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Sunday, Dec 22

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

  • Klarna Financing
  • Affirm Pay in 4
  • Affirm Financing
  • Afterpay Financing
  • PayTomorrow Financing
  • Financing through Apple Pay
Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

Similar Products

Top Amazon Reviews

    • Easy to use - Works great
Style: Bag Size: 24 x 1 Pound
I've been using Shock from Leslies for years at a higher price. The In The Swim Pool Shock works great and is much cheaper than what I have been using.
Reviewed in the United States on January 1, 2024 by BHuss
    • Works as it should
Style: Bag Size: 24 x 1 Pound
Product is great. Quick shipping. Same price as their website.
Reviewed in the United States on December 12, 2023 by ShawnM
    • Cheapest way to Chlorinate and add Calcium
Style: Bag Size: 24 x 1 Pound
As long as you are NOT 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 Cyanuric Acid (CYA), which should never exceed "30" for a residential pool. This product WILL also stabilize and raise pH, so you can buy less bicarbonate and reduce pH fluctuation. This product is a NO brainer as the best cheap source of chlorine for ANY pool (unless you do not want to increase water hardness (calcium) ). Stable 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! By the time you buy that liquid chlorine, it has probably already degraded a couple percent. The production date on the liquid chlorine is usually at least 50 days old. Learn to read the production date on liquid chlorine sold at HD or Lowe's and do not buy if it is old. The first digits are the year, the next set of digits is the day of the year. For example, a stamp that begins ...20366 will be December 31, 2020. NEVER toss powdered chemicals into pool unless they are pure chlorine. Powdered chemicals just sink and do who knows what to your pool surface. Always mix first in 5 gal bucket, stir, then add to water. I do this a couple times to fully dissolve the calcium. OF COURSE the water will go cloudy - it is *Calcium* HypoChlorite, but the cloudiness only lasts a short time. Most pools do not have enough calcium hardness - I keep mine well above 400 so I can keep the pH low for better chlorine efficacy. This product also avoids the cost of separately buying a calcium enhancer for the pool. Because it has no stabilizer it will not raise your CYA. Final point : Focus on maintaining LSI. This keeps the water from being corrosive or depositing calcium on the surface. I recommend the free Orenda app. Plus -- unlike liquid chlorine, 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! Minus -- mixing it up before adding to pool takes a couple minutes you have to be careful to avoid splashing, which will ruin your clothes. You also have to cut the packet with a knife or scissors and avoid spilling any. Highly recommended ... show more
Reviewed in the United States on April 3, 2021 by RJacobs
    • Hard to remove lid, but works well.
Style: Bucket Size: 25 Pound
I even read reviews trying to figure out how to get the lid off. It wasn’t easy. Some people didn’t have problems but some others did, I needed a hammer and pliers. It is only initially that it is hard to open. You should always dissolve in a bucket before adding to pool. Works very well.
Reviewed in the United States on October 5, 2023 by KristyI
    • SEEMS EXPENSIVE, BUT IT WORKS TO KEEP THE POOL SPARKLING
Style: Bag Size: 24 x 1 Pound
I like that it really does work. I was educated to shock regularly and use fewer chlorine tabs to better keep my chemicals within desired range. I use this shock in combination with the same company's pool tabs and for several years now, my pool has had no problems requiring intervention by a pool professional. In the long run, it has saved me money. It has also given me peace of mind regarding the occasional times I miss my scheduled pool care day because of my health. I've never ever had algae of any kind while using this product. I highly recommend IN THE SWIM pool care products. They are fresh and effective. ... show more
Reviewed in the United States on September 12, 2023 by LG
    • Great flavor?...Not sure.
Style: Bag Size: 12 x 1 Pound
Why would they ask me the flavor? LOL. anyway, my third purchase. Best prices usually here at Amazon for pool supplies. Very effective shock. Keeps the water crystal clear.
Reviewed in the United States on October 19, 2023 by S. Ryon
    • Good
Style: Bag Size: 24 x 1 Pound
Good value
Reviewed in the United States on December 24, 2023 by Vicki Florido
    • Shockingly good
Style: Bag Size: 12 x 1 Pound
This is great pool shock!
Reviewed in the United States on December 13, 2023 by alyssa gilman

Can't find a product?

Find it on Amazon first, then paste the link below.