Salt Water Generator / Intex Pool Question/advice

[Indywar]

Thanks for the reply PoolDoc.

Sometimes it is better to be lucky than good I suspect there has been a fundamental engineering change to the SWCG (in addition to adding a copper generator that is useless) that has caused the change.
But anyways, the sodium chloride (salt) is measured by a dipstick and/or a conductivity meter, not by any chemical means. The pH probes is indeed calibrated with Fisher scientific pH 4 and pH 7 standards (I am a chemist and microbiologist during the day, and easily have access to the expensive pH meters to have an orthogonal technique to compare my pH probe to. In addition, I have used the phenol red (significantly less sensitive than our pH meters), yet another orthogonal technique, to confirm the pH probe readings).
I think I mentioned previously that I did have a test kit (OTO style), but if not my omission. I purchased a 6 way kit tonight, and have posted the results in a previous thread (approval pending).

I appreciate the advice to try to get things under control without the SWCG, trying to isolate if that is truly the problem. That is a good plan. I will also follow the advice with the sodium hypochlorite and report back.

Thanks again for the advice,
Rob

[PoolDoc]

But anyways, the sodium chloride (salt) is measured by a dipstick and/or a conductivity meter, not by any chemical means. The pH probes is indeed calibrated with Fisher scientific pH 4 and pH 7 standards (I am a chemist and microbiologist during the day, and easily have access to the expensive pH meters to have an orthogonal technique to compare my pH probe to. In addition, I have used the phenol red (significantly less sensitive than our pH meters), yet another orthogonal technique, to confirm the pH probe readings).

Not the response we usually encounter! But, you did lead me astray with this:

I measure the chloride using the drops (HTH 3 way kit)

(Shame on you!)

Shocking is not the hazard it's made out to be. People are very chlorine resistant -- though swimwear is not!

Anyhow, we'd gradually been moving toward a full blown rejection of all the NSPI / APSP / CDC / EPA "Keep people out of the pool till the FC is less than 3 / 5 / 10 ppm", though we hadn't quite gotten there. Now, we have.

I've known for some time that those regulatory limits were pulled out of the air. But until recently we didn't have positive confirmation of the safety of high levels of FC exposure. But, we had the issue raised this spring, and in the investigation that followed, I found that an old dermatological treatment, a "bleach bath" (> 50 ppm FC), is STILL actively and regularly prescribed for a variety of skin problems. Here's the link to a Google search on the topic.

So, when you shock, let it circulate long enough so their suit (or eyes) won't hit a hot spot . . . and you're fine!

[aylad]

But make sure that whatever's using the chlorine is dead--it's not the level of the chlorine that is a concern, so much as the fact that if the chlorine is fighting something in the water, then there's not any left over to fight additional people-goo, and if somebody in the pool has any sort of virus, the chlorine won't be available to act on it....

[Indywar]

PoolDoc, my bad. Amazing the difference in a couple of letters: chloride, chlorine, nitrate, nitrite, etc. You are right to scold me for not being accurate

It is amazing the paranoia the government, and in particular the yahoos in the EPA cause. As a scientist I am skeptical of anything coming from the EPA, the Center for Science in the public, and similar NGO that don't have any relevant data to back up their claims. Often they will cite some obscure study in the hinderlands of France with a maximum of 100 subjects, and then claim the 300 + billion people on the earth will be similarly affected. (Sorry for the soapbox).

Thanks for the advice. Will get to the shocking. Also, should I continue to increase the CYA. The pool place has a broad range of 30-150 ppm. Is higher better in this case?

Aylad,
Good point, although I am less concerned with the viruses as opposed to water borne bacteria. The cells of virus are more susceptible to disinfectants, even low levels and are incapable of reproducing without a host. Bacteria commonly grow in water environments (e.g biofilms that are at water fountains, in water coolers, etc.). Nonetheless, still good points.

Thanks again for all the advice. I have some work to do to get this stabilized.

Rob

[PoolDoc]

Good point, although I am less concerned with the viruses as opposed to water borne bacteria. The cells of virus are more susceptible to disinfectants, even low levels and are incapable of reproducing without a host. Bacteria commonly grow in water environments (e.g biofilms that are at water fountains, in water coolers, etc.).

As far as we know, the high risk events in pools are all related to person-to-person transmission, usually fecal-pool-oral or snot/spit-pool-oral. And, the culprits are usually either viruses OR amoebic oocysts. The data I've seen suggests that pathogenic viruses are MORE, not less, resistant to chlorine. Also, though these cases are not biofilm related, they ARE fomite related, and killing fomite associated pathogens is a LOT harder than killing planktonic pathogens!

There some common low risk events, associated with P. aeruginois and biofilms (hot tub itch; otitis externa) but those don't kill anyone or even make them very sick.

One rare exception: Naegleri fowleri is VERY dangerous and can actually live in pools, apparently.

Right now, the pool is the problem -- but this fall, if you are interested, it would be very helpful to have a working microbiologist looking over my shoulder as I'm putting SwimmingPoolResearch.com together. I've got about 8 Gigabytes of peer-reviewed articles to index!

Oh, and you're preaching to the choir, at least with me, about trusting "scientists" and especially government "scientists". Here something my older son (a recent biochem grad) found for me:

"It has long been known"... I didn't look up the original reference.
"A definite trend is evident"... These data are practically meaningless.
"While it has not been possible to provide definite answers to the questions"... An unsuccessful experiment, but I still hope to get it published.
"Three of the samples were chosen for detailed study"... The other results didn't make any sense.
"Typical results are shown"... This is the prettiest graph.
"These results will be in a subsequent report"... I might get around to this sometime, if pushed/funded.
"In my experience"... once.
"In case after case"... twice.
"In a series of cases"... thrice.
"It is believed that"... I think.
"It is generally believed that"... A couple of others think so, too.
"Correct within an order of magnitude"... Wrong.
"According to statistical analysis"... Rumor has it.
"A statistically oriented projection of the significance of these findings"... A wild guess.
"A careful analysis of obtainable data"... Three pages of notes were obliterated when I knocked over a glass of pop.
"It is clear that much additional work will be required before a complete understanding of this phenomenon occurs"... I don't understand it.
"After additional study by my colleagues"... They don't understand it either.
"Thanks are due to Joe Blotz for assistance with the experiment and to Cindy Adams for valuable discussions"... Mr. Blotz did the work and Ms. Adams explained to me what it meant.
"A highly significant area for exploratory study"... A totally useless topic selected by my committee.
"It is hoped that this study will stimulate further investigation in this field"... I quit.

[Indywar]

Hi Ben,

Sorry for not replying sooner, but my computer crashed, yet again. Let me know when you need a hand with the micro stuff, and I would be glad to help. I have followed the advice that has been given here and think the pool is finally stabilizing. I had reverted to bleach and shock to keep the chlorine levels higher, especially with this hot days and higher use. It seem the pH and chlorine have both settled into a normal expected range. Thanks to everyone on the forum for the troubleshooting advice and assistance.

Rob

[PoolDoc]

Glad things are working out for your pool.

If your computer problems are related to security, you may want to read this article sooner, rather than later:
http://news.discovery.com/tech/dns-c...ay-120426.html

I'm expecting to 'lose' quite a few PoolForum members that day!

I'll flag your member record as being a biologist, and will try to get in contact once things slow down a bit.