Moving the local technique

[buckdendave]

Yes ClO2 would be very good if it weren't for the side effects, but you wouldn't let the stuff be used by a regular pool professional because they just don't have the chemistry knowledge and it's too darn dangerous if used incorrectly. 

The concentration we use is only a few ppm.  We use a temp of 40C in order to get a rapid effect, and it takes a few weeks to demolish an EPDM O ring, for example.  We will be doing more work at lower concentrations and temp but it'll take some time to work through the programme.  You don't work with ClO2 without taking a lot of precautions and controls to constantly monitor and adjust concentration and pH.  For safety reasons the generation kit is in a concrete blockhouse outside the lab and its piped in solution through the wall to the loop.

Dave

 

[Théière]

[quote user="buckdendave"]

 but you wouldn't let the stuff be used by a regular pool professional because they just don't have the chemistry knowledge and it's too darn dangerous if used incorrectly. 

Dave

[/quote]

I do hope this is the last un-intelligent comment from an intelligent chemist.  Should we take from that statement that you were born a post graduate chemist, was it genetically implanted?

OR did you go to an education institution, in which case it was something you learnt?

A comment from the likes of,  "Women will never be able to drive motor cars"

[:@]

[buckdendave]

Oh come off it teapot, I did say a "regular pool professional", and I am sure you know what I mean.  Most of these guys are pretty good at solving the usual problems, but don't kid me that most of them know any chemistry outside of their narrow field of experience, because they don't.  I have been watching comments on this subject on the forum for a year or two and I know that almost by instinct these guys know the right solutions (far better than I, by the way), but frequently I have seen attempted explanations of the chemistry behind it and they haven't been right (you aren't one of them).  Actually this doesn't matter because even if the explanation isn't right the problem has been fixed.  More power to their elbow.  Getting it wrong can have consequences, and chlorine is not exactlly benign, but follow some basic rules and all will be well.  Some things you can't mess around with, and ClO2 is one of them.  Yes people can make a damn good living by learning a trade and not getting a University degree and sometimes I ask myself why people bother, but don't tell me the world can manage without them.  Try going to witch doctor with a heart complaint.  I don't think so.      

Dave

[Poolguy]

[quote user="buckdendave"]

but frequently I have seen attempted explanations of the chemistry behind it and they haven't been right (you aren't one of them).  [/quote]

He is talking about me John.

Seems that that Dave thinks that I have a bit more schoolin to do to measure up.

Andrew

 

[Poolguy]

[quote user="chem geek"]Andrew,

The indophenol method is described [url=http://www.hach.com/fmmimghach?/CODE%3AMETHOD10200_40006110%7C1]here[/url] where the test for ammonia actually creates monochloramine so one must first measure the monochloramine amount before going further with the test to measure ammonia.  Otherwise, you just end up measuring the sum of monochloramine and ammonia -- not ammonia alone.  This is also described [url=http://www.chemetrics.com/analytes/ammonia.html]here[/url] (the second test -- salicylate method -- salicylate is a phenol; these tests are also described [url=http://www.hach.com/fmmimghach?/CODE%3AEX_NITROGENAMM1436%7C1]here[/url]).  In other words, you have to subtract the monochloramine amount from the ammonia amount (in similar units) or re-zero the measuring device in two steps as described in the Hach instructions.  The Palintest description [url=http://www.palintest.com/products-details.aspx?id=14]here[/url] (and in the ammonia section [url=http://www.completeleisure.ie/elements/download/palintest_comparitor.pdf]here[/url]) implies that these tests are designed for non-chlorinated waters.  If your specific test instructions didn't say to first measure monochloramine and account for that in the test, then monochloramine interefered with your result -- in fact, you likely just measured monochloramine (and technically, according to [url=http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TF4-4S7SV5B-2&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=a61791f39ab386ce23efd26e945c9262]this link[/url] it's literally monochloramine, inorganic chloramine, and not any organic chloramines such as chlorourea).  The Hach instructions give a nice summary of the test method as follows where it is clear that the test is really for monochloramine and that one creates monochloramine from ammonia using chlorine (that clearly reacts quickly since you only have to wait for 2 minutes at 25C or 77F):

Summary of Method
Monochloramine (NH2Cl) and “free ammonia” (NH3 and NH4+) can exist in the same water sample. Added hypochlorite combines with free ammonia to form more monochloramine. In the presence of a cyanoferrate catalyst, monochloramine in the sample reacts with a substituted phenol to form an intermediate monoimine compound. The intermediate couples with excess substituted phenol to form a green-colored indophenol, which is proportional to the amount of monochloramine present in the sample. Free ammonia is determined by comparing the color intensities, with and without added hypochlorite.

Figure 1 in [url=http://www.hach.com/fmmimghach?/CODE%3AL61351472%7C1]this PDF file[/url] shows the chemical reactions in the test where the first step is to convert any ammonia to monochloramine.  It should be obvious that if you already have monochloramine, then that is going to be additionally measured in the test.  It should also be obvious that the test itself counts on the fact that the first step, where ammonia and chlorine combine to form monochloramine, occurs quickly.

Also, if you have no chlorine in the pool water, then obviously any ammonia will persist as ammonia and will get measured as such.  It looks like one pool may have had that situation.  It looks to me like you ended up measuring the amount of monochloramine and not ammonia in the water, except possibly for the pool that had "no chlor" (what did you mean by this -- no chlorine?).

Ammonia is typically measured as mg NH3-N / L which is units of atomic nitrogen.  Monochloramine is typically measured as mg Cl2 / L which is units of chlorine gas equivalent.  There is roughly a factor of 5 difference in these measurements.  That is, 0.2 ammonia results in 1.0 monochloramine.  If your measurements of 5+ ppm ammonia were correct and measured in atomic nitrogen units, then if chlorine were present this would result in 25+ ppm monochloramine which seems unlikely.  Your "Andy" measurement was high at 5.65 yet used zeolite and said "no chlor" which I presume means no chlorine.  If that is the case, then with the zeolite there should not have been such a high ammonia so I strongly suspect that you were in fact measuring monochloramine in your tests and not ammonia.  Are you sure you did the test correctly?



Richard
[/quote]

Richard

 

I have now the response from Palin Test concerning your challenge to the validity of the results I am getting from Ammonia tests using their equipment. I quote below:

"I read the thread that you pointed me at and your detractor is half right with all the interesting text book information about reaction times and species formed but wrong about the scope of the indophenol test we use for ammonia.

 

The ammonia test using the indophenol method will pick up all the free ammonia and the monochloramine. The monochloramine is a volatile amine and at swimming pool pH is the main variant of chloramine produced. The only variant of ammonia that you will be missing is the dichloramine which can be determined using the DPD test method if you want to go so far but I don't think that is necessary."

 

 

Best regards

Ian Leahey

Chief Chemist

Palin Test UK

 

Now bearing in mind that Dr Palin (founder of Palin Test UK) was the inventor of the DPD method and first proposed 'Break point’ chlorination ' I am satisfied (at least) that the testing that I am doing is correct as it is advertised by Palin test to be an test of Free Ammonia present in Swimming pools and that the conclusion that the use of ZEOLITE as a filtration medium is effective in reducing Ammonia that becomes more and more clear to me. I will test further and build up a larger data bank of samples including pools tested BEFORE with sand and AFTER with Zeolite to reinforce the point. It shows that Free Ammonia is present in EVERY SWIMMING POOL at least to some degree, a conclusion which is Supported by Ian Leahey of Palin test UK

 

So my dear Mr Geek, notwithstanding your erstwhile opinion concerning what it is I am actually doing and saying, I would have to here suggest that your argument is not with me but with Palin test whom I suggest you direct your enquiries. I shall continue with my claim that ZEOLITE removes ammonia form chlorinated swimming pools and nothing yet has proven that it isn't so contradicting my more practical empirical method that proves (to me) that it is.

Here are some more results for you to reflect on.

 

AMMONIA EXPERIEMENT		mai-09
Domestic pools				Commercial pools
Owner	Sand	ZELEAU	Comments	Location	Sand	ZELEAU	comments
John 11		0,25	In balance	Le Brande17	0,45		in balance
Andy  66		5,65	green, no chlor	La Brande17		0,24	low TA
Muriell  17		0,21	green,CYN too high	Font Municip 85	0,04		Low chlor
Steve 85		0,33	In balance	Bohat Child 56	0,07		fresh water
Richard 85	4,56		Clear, indoor	Bohat Slide 56	1,29		Green
Dubois 17		0,29	Clear,	Bohat Covered 56	5,65		Green
Rod 17		0,13	Clear Resin
James11	3,6		Green Oxymatic

 

 

Note that the Result Andy66 (5.65) the pool was winterised and not circulating, I will ask for another sample now that the pool is functioning and retest. Also note that the results over 1.0mlg/lt were obtained by ‘cutting’ the sample sufficient times with blank water till the photometer was able to register a reading. They are therefore approximate as the method was not an exact halving, but results under 1.0 can be regarded as reliable.

 

I am willing to add to this list by way of testing any water that can be sent to me under reliable conditions so that a more complete picture can be developed.

 

So I hope that we have now arrived at a point where my response to your contradiction has been explained. But bear in mind that I am not challenging you to prove your theoretical construction but rather merely to verifying the validity of my experimental conclusions in order to make claims in the market place that I can support with such evidence. There is after all far too much poor or misleading information put forward in an effort to sell unnecessary or inappropriate products in the pool industry, which I think was the tenor of your original objection to my remarks.

 

Suffice it to say that this discussion, if it has not nothing else will I hope convince you and anyone else that cares to follow it that for my part at least, there is substance and integrity to my position.

 

Andrew

 

 

 

 

 

 

 

 

[chem geek]

[quote user="Poolguy"][quote user="chem geek"]Otherwise, you just end up measuring the sum of monochloramine and ammonia -- not ammonia alone.

  It should be obvious that if you already have monochloramine, then that is going to be additionally measured in the test.  It should also be obvious that the test itself counts on the fact that the first step, where ammonia and chlorine combine to form monochloramine, occurs quickly.

[/quote]

"I read the thread that you pointed me at and your detractor is half right with all the interesting text book information about reaction times and species formed but wrong about the scope of the indophenol test we use for ammonia.

 

The ammonia test using the indophenol method will pick up all the free ammonia and the monochloramine. The monochloramine is a volatile amine and at swimming pool pH is the main variant of chloramine produced. The only variant of ammonia that you will be missing is the dichloramine which can be determined using the DPD test method if you want to go so far but I don't think that is necessary."

I am satisfied (at least) that the testing that I am doing is correct as it is advertised by Palin test to be an test of Free Ammonia present in Swimming pools

[/quote]

Andrew,

Please re-read the response from Palin.  It is EXACTLY as I had described it (I don't know what they think is "half right").  The test you are using measures, and I quote Dr. Leahy, "free ammonia and the monochloramine".  Read that again until you see the words "and the monochloramine".  You cannot claim you are measuring ammonia with the test because it measures, and I quote this again, "free ammonia and the monochloramine".

Monochloramine is somewhat volatile, but not THAT volatile, especially when compared to nitrogen trichloride.  The Henry's Law constant (see [url=http://www.mpch-mainz.mpg.de/~sander/res/henry.html]here[/url]) for hypochlorous acid is around 930, for monochloramine it is around 94, for ammonia it is around 60, for dichloramine it is around 29, and for nitrogen trichloride it is around 0.1 where lower numbers are more volatile (equilibrium is more towards gaseous state than being dissolved in water).  The fact that one can even measure monochloramine in the DPD test fairly readily shows that it can't be so volatile as to not be measurable in pool water.

So please stop saying that you are measuring ammonia in every pool, at least those with measurable (non-zero) Free Chlorine (FC).  With the test you are using from Palin, you are measuring "free ammonia and the monochloramine" and are NOT distinguishing between the two.  You do not know whether you are measuring monochloramine or measuring ammonia since the test measures the SUM of the two!  This is what I had said and what Dr. Leahy confirmed.

Thank you for explaining details about the "Andy" pool and if after circulation the results are lowered then that would be a better confirmation of lower "free ammonia and the monochloramine", BUT realize that if there is no chlorine and there is ammonia, then adding chlorine will get rid of the ammonia through breakpoint chlorination and that will have nothing to do with the filter.  So the best pools to use would be those with measurable FC yet have CC or "ammonia" (really monochloramine) amounts and that this is lower in Zeolite filter pools than in sand filter pools.

If you would please use the DPD or even better FAS-DPD test to check not only the Free Chlorine (FC) level, but also the Combined Chlorine (CC) level of the pools you are testing, then that would help determine whether it is ammonia or monochoramine that you are measuring.  When there is no Free Chlorine (FC) in the water (such as in the Andy pool), then ammonia can be present and you can be measuring that (monochloramine could be present as well if there was some chorine earlier).  When there is Free Chorine (FC) in the water, then there will be no measurable ammonia present so what you are measuring is monochloramine.  This is where the DPD or FAS-DPD CC test comes in since that will measure monochloramine and not ammonia though unfortunately also measures other CC as well such as chorine combined with urea.

The bottom line is that if you show most or all of the pools with lower levels in your "ammonia" test or your CC test, then that's a good thing but does not mean there was ammonia in the pools at the time of your testing.  It means there was ammonia OR monochloramine (or a combination) in the pools (and if you measure non-zero FC, then I'm saying that it's monochloramine that you are measuring).  The fact that the zeolite helps lower the monochloramine level is still a good thing, but it is not because there is ammonia in the pool and that is what I was disputing since that is what you were originally claiming.  As I said earlier, the lower monochloramine can also come from better (finer) filtration which other filters (DE, AFM, etc.) could provide removing more precursors that could combine with chlorine.  Also, sand filters can get bacterial fouling which could increase CC levels (if Dryden is correct).

Again, chlorinated pools, those with measurable FC, do not have ammonia in them (except immeasurable equilibrium amounts), but may have monochloramine and other combined chlorine.

By the way, you never answered my question about what "green" meant.  Does that mean the pool is "green" meaning algae or that the ammonia test showed green?  Does that mean these pools have no chlorine in them (i.e. FC is zero)?  There isn't much point measuring pools without chlorine since that isn't how you are supposed to maintain a pool.  If one lets a pool go over the winter and doesn't maintain chlorine levels, then one can certainly end up with an algae bloom or have bacteria convert CYA into ammonia and one can end up measuring lots and lots of ammonia and monochloramine.  The value of a filter reducing monochloramine levels (through whatever means) is when the pool is being chlorinated, so when there is measurable FC.

Richard

[chem geek]

Andrew,

So I called up Dr. Ian Leahy early this morning my time (about 2:15 AM so I would catch him in the office) long-distance from U.S. to England and after I explained what I had written he said I wasn't half-right but was completely right.  He only very quickly reviewed my post you referred him to and did not realize that I was already saying that the indophenol test measures both (the sum of) monochloramine AND ammonia.  He agreed that in pools with chlorine (that is, Free Chlorine) there should be effectively no measurable ammonia because chlorine combines so quickly with ammonia to form monochloramine so any measurement in the indophenol test in such pools would be that of monochloramine.  He also confirmed that the indophenol test itself actually measures monochloramine and that the first step in the test adds chlorine to convert any ammonia to monochloramine for the subsequent steps and measurement.  That's why the test overall measures the sum of ammonia and monochloramine.

So except for pools where the Free Chlorine (FC) measurement is zero, please stop saying you are measuring ammonia in the pools -- because you aren't.  In pools with measurable FC, your indophenol test is measuring monochloramine (because there is effectively no ammonia).

Also, I asked Dr. Leahy about whether the Palintest reported in units of ppm-N as with ammonia or ppm-Cl2 as with chlorine or monochloramine since you reported such high numbers (e.g. 4.56 and 5.65).  He said that if you were using a Palintest instrument for the measurement, that "the nominal range of the instrument is 0 - 1 mg/l N so some dilution has been made and the high results may stem from that (either the diluent or the calculation)."  So can you please tell me exactly how you are doing the measurement since the instrument itself would only report up to 1 mg/L?  How are you getting your 4.56 and 5.65 numbers?

By the way, in the signature in the E-mail I received (I asked him a separate question via E-mail), the name is "Ian Leahy" without an "e" before the "y" and his title is "Export Sales Executive" though when I talked to him he clearly understood chemistry so may be their chemist as well (I didn't ask).

Richard