Power Blast Pool Shock (68% Cal. Hypo.) 1 Lb. Bag - R20841

Model # R20841

  4.79 Average  



Model # R20841

Product Description

Cal-Shock 65  

Power Blast Cal Shock 65 is 68%CalciumHypochlorite with 65% available chlorine. Our best selling shock treatment, Cal Shock 65 is in a fast dissolving granular form so it quickly destroys organic waste, algae and bacteria saving you time and money. 
  • 1 lb bags Calcium Hypochlorite
  • Powerful shock treatment great for spring start up
  • Gives quick chlorine boost
  • Ensure pool water is balanced for best results
  • Complete instructions for dosage on container
  • Compares To BioGuard Burn Out
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


?     Asked on 10/18/2012 by Guest

My pool company recommends using a phosphate remover. Do you have any such item?

A     Answered on 10/18/2012 by InyoPools Product Specialist Patrick P.

I would recommend using  Phosfree. The product container has easy to follow directions and will help you eliminate your phosphate problem.

?     Asked on 10/18/2012 by Guest

I have an in ground pool with a mesh winter cover. Several weeks ago, I had added 2 gallons of chlorine to the pool. Since then, with the mesh cover still on, the water has turned green. I've been adding about a gallon of shock each week without improvement. Should I continue adding shock to the pool or should I wait?

A     Answered on 10/18/2012 by InyoPools Product Specialist Patrick P.

I would recommend waiting until the pump and filter are running again before adding any more shock to the pool. Algae needs two things to grow: food and light. With a mesh winter cover, the algae has more than enough light to grow regardless of the shock that you're putting in. Also, shocking the pool without circulation can cause bleaching of the pool surface

?     Asked on 10/12/2012 by Guest

Can I add shock through my automatic chlorinator?

A     Answered on 10/12/2012 by InyoPools Product Specialist Patrick P.

No, you should never add shock through an automatic chlorinator. Never mix different types of chlorine. Pool shock can be added to a bucket of water and poured directly into the swimming pool.

?     Asked on 1/25/2012 by Guest

I'm looking for pool shock to sanitize my drinking water. Will this work?

A     Answered on 1/25/2012 by InyoPools Product Specialist Patrick P.

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.


Est. Repair Time

Less than 1 hr

Tools Needed

Scissors to open the shock

Poor Chlorination

Written on 4/19/2017 by Guest

I got rid of my old Chlorinator and installed a Rainbow 300-19 in it's place. I also switched from my old Shock and started using Robarb Power Blast Shock that I purchased from inyopools.com, the same place that I got the new Chlorinator from. PROBLEM SOLVED! I keep the Chlorinator on 1, and when the chlorine get's a little weak, after a week or so, I broadcast 1 bag of shock over the deep end of my pool and it snaps the chlorine right back to where it should be.

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Review Summary

  (Average 4.79 out of 5 stars)
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