New China Shop Topic: How Accurate is the Pool Calculator?

[chem geek]

The idea is just to start out with what is the most likely value -- that claimed by the manufacturer. As I wrote, it's not that important, but if you're going to have an automatic calculation you might as well start with the correct intended number. Errors accumulate so there's no point in starting with something you know is likely to be wrong.

6% Bleach doesn't degrade very fast because the rate of degradation goes roughly as the square of the concentration. 12.5% Chlorinating liquid degrades more quickly. See the chart at the bottom of this page. As for impurities, you'll note that this manufacturer does remove catalyst metals from their source water and I checked with Hasa on the West Coast who is the source of the chlorinating liquid I use as well and I also checked with Clorox about their bleach. Most of the big players take care to produce a quality product. I can't speak for the off-brand Ultra bleaches.

[PoolDoc]

Hi Richard;

I was sort of teasing, though I do think excessive precision is a bane of good pool care.

That said, because I bought, sold, and delivered 15% bleach for 15 years, I investigated bleach stability as much as I could, given the paltry Internet resources available at the time.

One possible oversight in your remarks above: according to the man whose company* made the bleach I started off with, the significant source of metal contamination of bleach was not the source water, but the chlorine liquid. Nickel and some other trace contamination originated in the manufacturing process; iron in the transport and piping process. Producing low-metal bleach required post manufacture filtration of the bleach itself. Fully effective filtration apparently results from the use of bleach tolerant micro-filtration.

So, based on what I was told, a bleach manufacturer who's hyping source water filtration is really just dodging the question.

The first company I purchased from did not even make high purity bleach at the time -- their business was build on selling to the cotton chenille makers in Dalton, Georgia, and it was a fast delivery, high turnover process. By the time I was dealing with them, their business was with cotton sock makers in Alabama. But even in summer, the bleach didn't decompose faster than their 2x weekly deliveries. The second company did make high purity bleach, but only on an erratic schedule, and my purchase volume wasn't large enough to change that schedule. However, water filtration would have been a non-issue for them both, since they were using limestone spring or well water.

Ben

* His father-in-law revolutionized bleach production -- so I was told -- by dumping sugar in bleach, resulting in the formation of gluconic acid which chelated the iron in the bleach.