Non-Stabilized Granules vs Liquid

[bob19]

Hi Folks,
This is my first full summer operating my pool. I moved less than two years ago. Pool was empty last summer. I appreciate all the knowledge I've obtained from this forum. I've been using 12% bleach from the local pool store at $8 a gallon. (free gal after buying 11) One of the employees suggested I try non-stabilized granules since I want to keep my CYA at bay. The product is Poolife Rapid Shock. Active ingredients 68% Calcium Hypochlorite, Other ingredients 32% but no listing as to what those ingredients are. Minimum available chlorine 65%. He said a 16oz package was the equivalent of a gallon of the 12% liquid. He also said because it's in granular form the sunlight doesn't break it down and I can add it any time of day thereby lasting longer in my very sunny pool. I was skeptical of this claiim but a $5.50 a package I tried four of them. What I've experienced so far is that the granules do take about 12 -18 hours to fully dissolve which may be the real reason for the longer breakdown time. All my attempts to research his claim come up as 'sunlight breaks down chlorine' period. I couldn't find anything on the web stating sunlight doesn't break down unstabilized granules. Any advice from the veterans here is greatly appreciated.

 

[Donldson]

He said a 16oz package was the equivalent of a gallon of the 12% liquid.

A statement I make often with pool store employees: "he's wrong". In your pool a gallon of 12.5% will raise your FC by 12.5 ppm (10,000 is easy with liquid chlorine) and a pound of 68% cal-hypo raises the FC by 8 ppm. It also raises the calcium level by 5.5 ppm. With the amount of evaporation you get in Tucson I doubt calcium is something you're typically needing, so that's something to consider. Also his comment about "lasting longer" is complete rubbish. Once the chlorine is in the water it's just chlorine. Doesn't matter where it came from. CYA protects chlorine in the sunlight, at an appropriate level so as not to overly blunt its effectiveness. Thus the FC/CYA Levels

Once you figure that you need 1.5 pounds of 68% cal-hypo to roughly match a gallon of 12.5%, the costs come out pretty much dead even. Given the possibility of calcium buildup and the difficulty you had adding it (don't let that stuff sit on plaster, it will bleach the color out of it) I don't think there's much benefit left to consider replacing it. Just a lesson in never listening to pool store employees.

 

[Mdragger88]

You didn’t find that info because it isn’t so.
The sun breaks down all chlorine. If u have stabilizer in the water the rate of breakdown is lessened whether the chlorine product itself is stabilized or not.
FC/CYA Levels
Cal hypo not only adds fc to your water but also calcium which I suspect in AZ u already have plenty of in your water. Too much calcium hardness will lead to scale formation.

How to Chlorinate Your Pool

Before chlorinating your pool, you should know these simple tips. Learn the best way to add chlorine to your pool.

www.google.com

Calcium Hardness - Further Reading

www.google.com