Polyquat 60 and PH

[mikefamig]

I am closing and added 1 quart of Polyquat 60 to my 16x32 inground pool. A couple of days later I checked the PH and it has gone off the scale to the high side. I added 14 drops of R5 acid demand to get it back to about 7.8. Nothing else has changed and the FC is 7.5.

I have searched the forum here and see a lot of people asking this same question but the answer is alway "NO" the Polyquat will not increase PH. If this is true then why have many of us experienced this?

I am out of Muriatic acid and wonder if it is really necessary to pour over a gallon of it into the water. I'm attaching the label of the PolyQ, any help would be appreciated.

 

[cowboycasey]

So the PH level of Polyquat 60 > Polixetonium chloride is 6.9 to 7.3 so that is not at all high... What it is doing after it is introduced to your water is unknown... I have never used it so I am not sure... Is it off gassing in some way to raise the PH level? I am sure someone knows..

Polixetonium Chloride

Polixetonium Chloride chemical information summary.

pubchem.ncbi.nlm.nih.gov

 

[mikefamig]

cowboycasey

If you look at the label in my photo you can see the chemical name of the contents.

Mike.

 

[mikefamig]

I have something strange happening when I perform the Taylor PH test. I use the usual 5 drops of R0004 and the sample turns orange. At first the test result is about 7.2 but if I let it sit for a while it climbs to 8 and above. Why is the result changing while the sample sits?

Mike.

 

[mikefamig]

I learned that the Polyquat is not causing my PH problem. It turns out that having my Free Chlorine at 7.5 is ruining the PH test results. I was aware that high FC would affect PH results but I did not think that 7.5 was too high with CYA=40.

Live and learn, Mike.

 

[mikefamig]

I called Taylor and learned that my Chlorine was too high to get a good PH test. The FC is 7.5 with CYA=40 and every time I tested the PH it would start out orange and then turn purple in a short time.

Taylor put me in touch with a pool tech who taught me that adding 1 drop of R0007 would eliminate the excess chlorine allowing the PH test to work. I took fresh water sample, added 1 drop of R0007 and the usual 5 drops of R0004 and got a 7.2 PH result that does not change color when left to sit.

Just thought that someone else can benefit from my experience.

Mike.

 

[mknauss]

None of the tests (excluding the CYA test which it has no effect) should be left to sit. When the color changes or clears as indicated, the test is over. The pH test should be read immediately, and then disposed of.

You can trust the Taylor pH test to 10 ppm FC.

 

[Texas Splash]

I called Taylor and learned that my Chlorine was too high to get a good PH test.

Mike, R-0007 is a chlorine neutrizling agent. So that may have worked, but FYI we never let the testing sample sit. Not for pH, TA, FC or anything. When you do that the color always changes. So once you receive your final color change, record it and discard the sample. Letting it sit and using R-0007 is really just wasting your reagent.

 

[duraleigh]

The TFP suggested guideline for accuracy of the pH test is that FC should not exceed 10 ppm. It has been 10 ppm for 14 years and there has never had to have been an adjustment to that. CYA has no effect on the pH test.

 

[Texas Splash]

I learned that the Polyquat is not causing my PH problem. It turns out that havig my Free Chlorine at 7.5 is ruining the PH test results.

Actually, to be clear .... as noted on your other thread HERE, it wasn't the FC level. It was the color changing after letting the FC sample sit for an extended period of time. Perhaps we'll merge those two threads as to avoid a mix-up in future discussions.

 

[mikefamig]

duraleigh

I know nothing of chemistry but on the advice of a Taylor tech, adding 1 drop of R0007 to the water sample before performing the PH test gave a good test. He claimed that the R0007 eliminated the excess chlorine that was interfering with the PH test.

Mike.

 

[mikefamig]

Texas Splash

I separated the two questions to avoid confusion.

It is not the FC test that was changing as it sat, it is the PH test and adding 1 drop of R0007 was the solution to that problem. The PH was never too high at all, it was a bad test result caused by the chlorine level according to the Taylor technician.

 

[mikefamig]

I understand what you all are saying about letting a test sit before reading it. This PH test starting rising seconds after mixing. It went from orange to purple in 15 seconds or less. Very unusual in my personal experience.

Mike.

 

[JoyfulNoise]

How did you test your FC level? It may be that 7.5ppm is actually higher in reality.

There is no need to use R-0007 as the pH reagent already has dechlorinating chemicals added to it that produce a minimal change in pH. Adding R-0007 to high FC water is known to cause changes in pH therefore rendering the test results useless.

If you have high FC, do this - mix a 1:1 solution of pool water with DISTILLED water. Then test pH. Doing that will cut the FC down by half but have almost no effect on pH (due to the much higher alkalinity of pool water compared to distilled water).

I’ve tested my pH with R-0004 all the way up to 15ppm FC with no problems at all and no need to add R-0007.

 

[mikefamig]

I like the idea of diluting the water with distilled assuming that the distilled water is neutral PH?
I'll give it a try, Mike.

I'm doing all tests with the Taylor k2006 test kit.

 

[JoyfulNoise]

Distilled water is typically at a pH of 6.9-7.0. It has zero carbonate alkalinity and no mineral hardness. Diluting a pool water sample with it doesn’t change anything since the alkalinity of the pool water will resist any changes to pH introduced by the distilled water. That’s why it works better than adding R-0007 because the thiosulfate in R-0007 chemically reduces the chlorine but that reaction causes a shift in pH.

 

[mikefamig]

Very interesting, I'll definitely give it a try

 

[mikefamig]

I would like to add to this conversation that 7.5ppm free chlorine has never caused a problem with my PH test in the past. It was after I added the Polyquat that the PH test started behaving badly. It appears to me that the chemical in PQ has something to do with this still. Not that it affected the PH level but it does appear to have affected the PH test result.

Mike.

 

[JoyfulNoise]

I would like to add to this conversation that 7.5ppm free chlorine has never caused a problem with my PH test in the past. It was after I added the Polyquat that the PH test started behaving badly. It appears to me that the chemical in PQ has something to do with this still. Not that it affected the PH level but it does appear to have affected the PH test result.

Mike.

You could test tap water and distilled water pH and see if your reagents are working as expected. Then try adding the tiniest amount of the PQ to a water sample and retest to see if there’s a noticeable change in the pH colors. It could also be that the higher FC level breaks down the PQ into smaller chemical fragments by oxidation and one of those by-products affects the pH indicator. It is know the chlorine and PQ interact but the by-products of those oxidation reactions can still act like an algaecide. Eventually chlorine will destroy all of the PQ which is why regular use of it through maintenance dosing is required. A one time use of it should have no long term effects on your pool water quality.

 

[mickey4paws]

My experience with Polyquat 60: I have only used it once, several years ago at closing. I added it and some time after I took a PH test. The test turned a very dark purplish magenta color, and this was an immediate test, as I never let my samples sit after testing. It freaked me out as the day before my PH was in normal range, probably 7.5. I just figured it must be some kind of reaction with the reagent and not a true indication of PH. I haven't used Polyquat 60 since at closing since it really didn't make a difference on how my pool was in the spring at opening.