Also, ftw, I have a degree in actuarial science and am well on my way to passing my second exam.
[ random fluff deleted - PoolDoc ]
And maybe all of that probably falls outside the expected scope of a forum like this, but...
well, it shouldn't.
Also, ftw, I have a degree in actuarial science and am well on my way to passing my second exam.
[ random fluff deleted - PoolDoc ]
And maybe all of that probably falls outside the expected scope of a forum like this, but...
well, it shouldn't.
Last edited by PoolDoc; 07-11-2012 at 09:40 PM. Reason: delete extended OT section
I said it once and I'll say it again. There is no "FREE LUNCH" when it comes to swimming pool sanitation. You're gonna pay the price somewhere, somehow, but burning my skin is not a price I want to pay.
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It doesn't help to move the goalposts around, so to speak. We started out talking about ocean salinity levels, but yes if we are talking about extraordinary salt saturation levels nearly 10 times higher then sure that may kill pathogens, but as was pointed out by others above is impractical for many reasons.
If we want to have a rational discussion about chlorine alternatives, we can have that, but why waste time going down dead ends? There are already quite a lot of alternatives we can discuss unless we're just having a brainstorming session online.
I didn't mean to discount the very real risks of chlorinated disinfection by-products. High bather-load indoor pools that aren't exceptionally well managed can be pretty darn awful in short-term effects (largely from nitrogen trichloride) and may be at least somewhat harmful for long-term effects (from brominated THMs and other chemicals, mostly regarding cancer). However, when I look at this data, I can see that reducing the active chlorine level to the lowest amount that still gives reasonable disinfection rates while simultaneously providing methods for removing organic precursors (i.e. bather waste) to oxidize them before chlorine does seems the easiest path to take, at least initially. I believe small amounts of CYA (20 ppm for indoor pools, for example) can be used for this purpose to have, say, the equivalent of 0.2 ppm FC with no CYA.
As for true alternatives, we need something for bulk-water disinfection and right now it looks like the quarternary ammonium compounds might be a reasonable candidate (I already discussed the problems with copper/silver, though for just preventing uncontrolled bacterial growth they are OK if one can deal with their levels and pH to avoid staining issues). UV or ozone can still be used to handle Crypto. That still leaves general oxidation of bather waste for which there are a lot of alternatives (ozone doesn't oxidize urea well, especially if it's not chlorinated, while UV only affects some chemicals). In addition to some selective oxidizers, such as MPS, the use of boron-doped diamond electrodes to produce hydroxyl radicals may be a good approach and might be one of the few things that can break down urea (other than chlorine, which does so slowly though possibly aided by the UV in sunlight that produces...hydroxyl radicals), though that remains to be seen.
And then there's the DIN 19643 system used in some countries in Europe that focuses on coagulation/filtration for removal of organic precursors, though they use low levels of chlorine in the 0.3 to 0.6 ppm FC range without ozone or 0.2 to 0.5 ppm FC with ozone (with no CYA, however, so still generally higher than I'm proposing).
Now for residential pools where person-to-person transmission of disease is a risk many would be willing to take since odds are they might catch something through other contact means (such as you described), then the focus is more on preventing uncontrolled bacterial growth and oxidation of bather waste. The same sorts of alternatives as described above could be used, but using a subset of them since the bather load is much lower. Just keep in mind that the risk is higher (though as a personal choice, may be acceptable) and usually the costs will be higher as well, at least up-front. I'm just very leery given my discussions with users of such systems when they failed, but realistically a properly designed system may not have the same problems as those that were used (or used improperly).
In other words, a bean counter for the insurance industry! Explains a lot. A FAR cry from the actual hard science disciplines like chemistry, biology, and physics. More akin to an accountant that understands some statistics.
Probability is better left to describing an electron's position in its orbitals or perhaps at the roulette wheel and craps table in Vegas (or to the insurance industries, which is basically just another form of gambling, that are betting that they can get your money without having to pay you for a claim. If you are high risk they won't insure you!) then to the care of a swimming pools!
Retired pool store and commercial pool maintenance guy.
Putting down someone's educational achievements, the job he holds, and the industry in which he works really isn't germane to this discussion.
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I was merely pointing out that his expertise is in a different field and not one related to pool water sanitation such as chemistry, microbiology, medicine, etc. or even pool maintenance and operation for a variety of pool and not just his own.
His expertise would be in accounting and risk management (which is where the probability comes in).
I stand by everything I said and it was not a put down. It was a statement of fact. Just because one has higher education does not make them an 'expert' in areas not related to what they studied, not does it necessarily give them critical thinking skills (particularly nowadays).
Retired pool store and commercial pool maintenance guy.
I smiled at your post WB, but, AnnaK's right: "bean counter" is a perjorative. It also appears that you've swung a bear claw at catfish, the insurance indistry, and the statistical sciences.
On the other hand, I absolutely agree that catfish's assertion that a degree in actuarial science (+ one exam) validates these assertions is rubbish. I have observed that a high level of achievement in a particular field tends to engender a belief that the models and methods of one's expertise are universally applicable especially when these achievements are new. I have also observed that many if not most people make decisions based on loose conjecture, casual observation, and percieved consensus. They depend on a "sense" or "feel" of the world with no understaning of the facts or mechanisms surrounding thier decisions.
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