Powdered instant liquid chlorine

[Nasantos]

I was looking through a "in the swim" catalog and saw they have 1lb bottles of powdered liquid chlorine that they say are equivalent to 1 gallon liquid chlorine. They run about $5/lb and would seem to be a little more expensive than liquid but a lot more convenient. Will this product work as a substitute to liquid chlorine and tfp care method?


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[chem geek]

As noted in this MSDS, this is 73% Cal-Hypo. This is terribly deceitful of intheswim not to identify this anywhere except on their bottle. For every 10 ppm Free Chlorine (FC) added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm. One pound of 73% Cal-Hypo is equivalent in chlorine (FC) as one gallon of 8.25% bleach, namely 8.7 ppm FC per 10,000 gallons.

They are naming this differently in part so that they can charge more than if they called it Cal-Hypo. At 4*1.07 = 4.28 pounds for $21.99 this is $5.14 per pound (or $4.97 per pound for 32 pounds). You can get the same 73% Cal-Hypo in GLB SuperSonic at poolgeek.com for $3.71 per pound or Leslie's Power Powder Plus for $4.00 per pound (or Power Powder Pro for $3.00 per pound but that's for 100 pounds).

If your CH is low, then you can use Cal-Hypo as a source of chlorine that also raises the CH or if you find it's price much lower than chlorinating liquid or bleach and you have a vinyl pool with low CH, then you can use it at least for a while. As with any concentrated chemical, make sure to add it slowly over a return flow with the pump running and brush the pool surfaces in the area where you add the product to ensure thorough mixing. Cal-Hypo does not dissolve as readily as some other granular chlorine products (such as Dichlor or lithium hypochlorite).