Cal Hypo Change

[anotherpyr]

My last cal hypo purchase was a 75lb HTH bucket at Costco back when it was 75% (or close to that) cal hypo. When did the industry change to 48% and why (other than greed)?

I have an IG with a vinyl liner so as long as the calcium level is low I like using cal hypo since it weighs less and has a longer shelf life than 12% bleach.

[jonv112]

I bought my cal-hypo bags at Costco this summer and it was 68% chlorine.

[anotherpyr]

I bought my cal-hypo bags at Costco this summer and it was 68% chlorine.

I have seen some bags that were 68%, but the buckets all seem to be of the 48% chlorine type. Also some of the bags seem to be a trichlor variety of chlorine.

[chem geek]

Take a look at this thread for more info on this issue.

A product with 100% pure Calcium Hypochlorite would have [EDIT] 99.2% available chlorine because the molecular weight of calcium hypochlorite is about double that of chlorine gas, but provides twice as much disinfecting chlorine per molecule so calcium hypochlorite and chlorine are roughly equivalent in available chlorine. [END-EDIT]. I saw one Material Safety Data Sheets (MSDS) that says 65-71% of the product (by weight, presumably) was calcium hypochlorite, but claimed to have 65% minimum available chlorine which [EDIT] is [END-EDIT] correct. Some products I've seen say they are composed of 60-80% Cal-Hypo (and call themselves "65"). Check the MSDS to see the actual weight percentage of calcium hypochlorite -- if it's less than 100%, then this is a diluted product with other inert materials you pay for, but that don't do anything.

I looked for, but could not find, a source for pure calcium hypochlorite except for small quantities that were expensive and used in labs. There could be something out there, however, that I couldn't find. Perhaps the bags you saw at Costco are your best bet, ***uming the price per pound isn't too high.

Richard

[chem geek]

I corrected my previous post because I am such an idiot. I had already put a percentage of 73% for calcium hypochlorite in my spreadsheet which is why I thought it would produce lower available chlorine. I was wrong...dead wrong.

So, calcium hypochlorite and chlorine gas are nearly equivalent with regards to available chlorine. So if you get 65% calcium hypochlorite, then this is about 65% available chlorine. Sorry for misleading anyone earlier.

Richard

[CarlD]

I believe that, in addition to WalMart wanting a lower price point and HTH giving it to them, the other reason for 48% is warehouse safety. From everything I've read, Cal-Hypo is the most reactive of the common chlorinators we use. I also believe WalMart had a major warehouse fire due to something or other with 68% cal-hypo.

[Tomcat]

I bought a bucket from Leslies, on sale, and it's 73%.