Model # R20841-48
Cal-Shock 65 – Fast-Acting Calcium Hypochlorite Shock
Powerful Pool Shock Treatment for Crystal Clear Water
Power Blast Cal-Shock 65 delivers a quick and effective chlorine boost with 68% Calcium Hypochlorite and 65% available chlorine. This fast-dissolving granular formula is perfect for destroying organic contaminants, algae, and bacteria, making it a top choice for weekly maintenance or spring pool openings.
Key Features:
High-Strength Formula – 68% Calcium Hypochlorite, 65% available chlorine
Fast-Dissolving Granules – Acts quickly to sanitize and clarify water
Effective Shock Treatment – Great for weekly maintenance or heavy pool usage
1 lb Convenient Bags – Easy to use, no measuring needed
Ideal for Spring Start-Ups – Quickly restores water clarity after winter
Made in the USA – Quality and reliability you can trust
Usage Tips:
Ensure water is properly balanced before application
Apply in the evening or when sunlight is minimal
Follow dosage instructions on container for optimal results
Compares to BioGuard® Burn Out
Restore sparkle and hygiene to your pool fast with Cal-Shock 65—your go-to solution for reliable and affordable water care.
| Pool Volume in gallons | Amount of Shock needed weekly if pool is clear | Amount of shock needed if pool is green |
| 10,000 gallons | 1 lbs. | 2 lbs. |
| 20,000 Gallons | 2 lbs. | 4 lbs. |
| 25,000 Gallons | 2.5 lbs. | 5 lbs. |
| 30,000 Gallons | 3 lbs. | 6 lbs. |
| 35,000 Gallons | 3.5 lbs. | 7 lbs. |
| 40,000 Gallons | 4 lbs. | 8 lbs. |
*Always follow the manufacturer's recommendations/directions located on the product container.Store any un-open bags in a cool and dry location
For More Pool Chemicals
I'm looking for pool shock to sanitize my drinking water. Will this work?
Reply
I have heard of people using pool shock to sanitize drinking water but I can not promote the use of any pool shock for this purpose. You will want to contact the NSF for further information.
Reply
No matter how much chlorine shock I put in my pool the chlorine level is always low. What can I do?
Reply
I would first make sure that you are testing the total chlorine AND free chlorine. If they are not the same reading, you may have a chlorine lock. If the chlorine levels are the same, I would check the pH, alkalinity and cyanuric acid levels.
Reply
Is it true that if I have a vinyl pool I can only use liquid shock?
Reply
You can use granular or powdered shock with a vinyl pool as well. Before adding the shock to the pool, you want to add it to a bucket of pool water to pre-dissolve it.
Reply
My swimming pool is clear but when my kids and I went swimming, our eyes burned. My neighbor came by and checked and said that the pool should be fine because he can smell the chlorine. What is wrong with my pool?
Reply
I think I have a chlorine lock in my swimming pool. How did I get it and how can I get rid of it?
Reply
The Most Helpful Review
6 0
(5 out of 5 stars)
Reviewed By: Russell J. from Myrtle Beach, SC ()
This shock clears the water nicely
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The Most Recent Reviews
4 0
(5 out of 5 stars) Great Price
Reviewed By: Bob D. from Bayville, NJ ()
Pros: Easy of use
Easy to use and great price
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