Hi from NSW, Australia

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It's up to you. I have the Aussie kit as well and I never use the DPD chlorine test. It is good for a 'yep I have chlorine kind of thing' but it maxes out at 5 FC. My FC is never that low so I rely purely on the FAS- DPD test to read for higher levels of FC and I can also feel secure that I'm staying above the minimum FC for my CYA at that particular time.

In Summer I'll test at least every 2nd day and in winter twice a week.
 
Thanks for that Jezza

Since I'm new to this thing and the $hop made buy 10 bucks worth of this tablets, I was wondering if I could actually use them.
I like the way you describe them: 'yep I have chlorine kind of thing' --- That's all they've been doing to me.

Got back home very late from work.
Will test tomorrow. Like Jet said, it's so cold everything is in slow motion....
And I'm not overly concerned. Pool's been crystal clear for months using 4-in-1 and $hop testing.
I just won't add anything stupid recommended by the $hop.

Quick question though. My MA is labelled at 32% but pool math use 31.45% - 20o Baume (that must be a USA thing). Is it ok to follow pool math recommendations or just underdose a bit to compensate the difference in concentration?

Also in case I need to SLAM, what Aussie bleach would you recommend?

Cheers
 
Yep the hydrochloric acid will be insignificant in difference so just use the 31.45%, For your sized pool you'll probably find 100 ml will be just shy of 0.1 reduction in pH.

Liquid chlorine is the way to go in Australia- our bleach is too weak!! Bunnings is usually a good bet although your local pool store might have a reasonable price and most do the deposit on a container and then just change over and are fairly competitive in price. You just need to shop around- but I like supporting my local pool guy even if I don't buy much else. ;)
 
Safety alert - don't let either of them get in your eyes, not even a drop. Pick up some safety glasses if you don't have any. On the skin is no big deal, just rinse off within a few minutes, but eyes are a risk.
 
Hi all

As I mentioned before I had to re-test my CH as I was unable to achieve a proper reading.

Following jet's and CCL's advice, I used the CH standard that came with my CCL kit and I did return a (blue) reading of 200ppm (8 drops) which means my reagents are working.

I tested my pool water again tonight, taking my time carefully following the steps.
The compound turned pink initially but never turned blue and stayed in the yellow-ish colour from roughly 200-250ppm (8-10 drops). Since CCL is sending me additional CH reagent, I thought I'd keep pouring but I never achieved any kind of blue.

Any thoughts?

Cheers
 
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Not sure what your reagent numbers are but do this -

Add 5 drops of the titrating reagent (Taylor calls it the R-0012) BEFORE ADDING ANYTHING ELSE.

Add the required number of drops of the calcium buffer reagent (Taylor R-0010)

Add indicator dye (Taylor R-0011L)

Then add titrant dropwise and count. Look for the color transition. Sum together all drops of titrant added.

Let us know what happens.
 
Yann,
R-0012 is equiv to CCL #4 Calcium titrating reagent
R-0010 is equiv to CCL #2 Calcium hardness buffer
R-0011L is equiv to CCL #3 Calcium detection reagent

Thanks for that option, Matt :)
 

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G'day!

I have re-tested my pool water with a new set of reagents and I got the same results as previous.

Following above recommendations I added 5 drops of titrating reagent first, followed by buffer (at this stage compound is still clear), followed by detection reagent. I could see blue drops in the compound as previously, but then the compound turned straight to yellow-ish - no pink at all - then I carried on with the titrating reagent: dropwise, shaking for 20-30 secs between drops. I stopped at 35 drops (40 in total) without any colour change but the same tint of yellow-ish.

Any ideas or thoughts? there is definitely something in my pool water interacting with the CH test.

Then I proceeded to test my tap water (Sydney water):
FC 1.5
CC 0
pH top range 7.8 (could be more)
CH 75 (test went textbook reaction)
TA 40

Thank you for your input.
Mostly my question is: Is my pool safe? For swimming I guess it is (except for temperature 11C/52F), but is it dangerous to itself (surface or equipment damage...)

Cheers
 
Try one more thing.

Do as I said above, but don't add any CCL #2 calcium hardness buffer. Just add a few drops of the CCL #4, then the CCL #3 complexing indicator and then the remaining drops of CCL #4. And only titrate to an endpoint (ie, no more color change), so if it turns yellow again then stop when the yellow stops changing its hue.
 
Hi Yann and TFP experts!
This is an interesting one. Did you still get to 8-10 drops total before it went yellow? So the 5 before and then another 5 after, or did it go yellow pretty much straight away after reagent #3.

I've only had one other person with yellow CH tests and we never resolved it because they had another issue with their pool which made them do a refill and the problem went away. Same reagents before and after their refill but different results. I've shipped this question to the resident chemist to mull over. I'm glad the TFP crew is looking at it because I've got lots of questions and no answers. I would love to know why it's doing this because I'm sure it'll do it again. At least we know the reagents and your testing methodology are working, so we can narrow it down to something in the water *cue Jaws theme*

Scientist thinking hat on and throwing things out there:
1. Cold water can effect test results, so try leaving your sample in your pocket for a bit before testing it? I've had many a cold state customer have no problems though.
2. As you don't know what the previous owner put in the pool they could have put something weird in which is effecting the test, but then you've inherited this pool which seems to have pretty decent numbers so I suspect they haven't. No suspect bottles tucked in the back of the shed or under the pool pump?
3. Standard advice but from your other results it looks like you've gotten this right - Collect the water sample away from inlets/outlets where you might get artificially high readings of chemicals.
4. You see blue drops when you add #3 but the whole solution itself when you swirl/shake doesn't go blue does it - the blue drops disappear into solution? Going blue here would imply CH 0 and I don't think we're seeing that.

Joyfulnoise's suggestion will definitely help us all out with getting further down the path of solving the yellow mystery.
 
BrettClearChoiceLabs said:
Joyfulnoise's suggestion will definitely help us all out with getting further down the path of solving the yellow mystery.
Click to expand...

It's not all that mysterious.....

Eriochrome black T (also known as Solochrome Black or Sodium 1-[1-Hydroxynaphthylazo]-6-nitro-2-naphthol-4-sulfonate) is the standard metal ion indicator dye for these types of complexometric analyses. It has three deprotonation constants - below a pH of 5.5, the indicator is red. Between a pH of 7 and 11, the indicator turns blue and above a pH of 11.5 the indicator turns a yellow-orange color.

There are several possible interferences from various metal ions - magnesium will cause the indicator to change from blue back to red (as does calcium). Copper and iron can both be chelated by the dye and so that will affect the color change as well because they act as blocking agents. The metals form a strong complex with the dye and, once formed, cannot be removed by EDTA causing permanent partial color change to red. This permanent red color is what causes there to be a purple end point instead of blue. Because the chelating strengths of the dye and titrant are close to one another, there can be a partial removal of metals from the dye causing blue to appear and then a fade back to purple as the dye absorbs the metals again (fading end point). In order to separate out magnesium from calcium, sodium hydroxide is used to precipitate magnesium hydroxide (an insoluble compound below a pH of 12.5). This is usually done by adding the sodium hydroxide up to a pH of about 10.5. Then, when you add the indicator, it's in the correct pH range to turn from red to blue as the chelating agent removes calcium from the dye.

The problem of yellowing is typically caused by unbuffered titrant drops. The EDTA-Ca complex formation is usually carried out at high pH (above 10.5) but the overall solution pH can't rise above 11.5-12 or else you'll get yellow instead of blue. So, at least for the Taylor titrant drops, the pH is tightly controlled using buffers as well as some additional chelating agents to improve performance when metal ions are present.

So, at the end of the day, it could simply be a problem of pH and insufficient solution buffering where the resulting mixture is getting too high in pH. This is usually a problem with the batch chemistry of either the dye or titrant and so, if it cannot be solved at the users end, it needs to be addressed at the supplier end. Either way, the yellow end point can serve as the end-point for the test, it's just a lot harder to see a final yellow hue change than a hue change in blue colors.
 
Hi Matt and Brett

First Brett I would like to thank you for the awesome customer service you provide. Your help and support on this issue, by email and now here, are greatly appreciated.

Matt, reading your posts takes me back 30 years when I was in my "nerdy" (no offense) teenage years and crazy about chemistry! I love it!!
your insights are very valuable.

I will try your 2 methods in the morning (no buffer and warm sample)

To answer Brett's question about CH test, it went yellow after #3, so only 5 drops of #4. And no it doesn't go blue. It's either pink/red or yellow. The only time I see blue is when the drops of #3 swirl to the bottom of the tube.
Re chemicals, nothing funny in the shed. An old bag of dry acid which I've thrown away months ago, some scale remover, some 2-in-1 clarifier/flocculent, an opened jar of non chlorine shock powder which I was going to throw away, some TA up, some phosphate remover which I've discarded too, some SWG cell cleaner. And acid of course.
I don't know how to post pictures so maybe I can email them to Brett if necessary?

thank you all for your help.
 
There are actually three standard indicators used for calcium determinations in the presence of magnesium - Solochrome Black, Solochrome Dark Blue and Calmagite. The Solochrome Black and Calmagite will both suffer from yellowing out at high pH (Calmagite actually turns a reddish-orange) but Solochroime Dark Blue will not. From the MSDS, Taylor uses Solochrome Dark Blue to achieve a more stable endpoint while also adding the high pH buffer triethanolamine.

This dye formulation is much less susceptible to yellowing out than other indicators.

- - - Updated - - -

yann said:
Hi Matt and Brett

First Brett I would like to thank you for the awesome customer service you provide. Your help and support on this issue, by email and now here, are greatly appreciated.

Matt, reading your posts takes me back 30 years when I was in my "nerdy" (no offense) teenage years and crazy about chemistry! I love it!!
your insights are very valuable.

I will try your 2 methods in the morning (no buffer and warm sample)

To answer Brett's question about CH test, it went yellow after #3, so only 5 drops of #4. And no it doesn't go blue. It's either pink/red or yellow. The only time I see blue is when the drops of #3 swirl to the bottom of the tube.
Re chemicals, nothing funny in the shed. An old bag of dry acid which I've thrown away months ago, some scale remover, some 2-in-1 clarifier/flocculent, an opened jar of non chlorine shock powder which I was going to throw away, some TA up, some phosphate remover which I've discarded too, some SWG cell cleaner. And acid of course.
I don't know how to post pictures so maybe I can email them to Brett if necessary?

thank you all for your help.
Click to expand...

Two things here - addition of scale inhibitors will skew the CH hardness test lower than true calcium levels because the scale inhibitor binds up the calcium to where it can not be detected by the standard CH test. Also, NEVER add clarifier and scale inhibitor at the same time! Doing so will cause a massive cloudy mess in your pool that will take days to clear or may not clear at all...
 
I've never used the scale remover in the 3 months I've had the pool.
I've used the clarifier once at clarifier dosage, not flocculent, the help clear up the pool after a storm. There was tiny organic particules all over the pool that my skimmer and Polaris could not capture. It did help with removal of those particles.

Now to my CH testing this morning:
interesting fact!
I must have confused my reagents yesterday.
This morning I used the fresh kit that Brett sent me (I thought I did yesterday with similar results) and I proceeded with standard test.
I got a textbook reaction at 13 drops= 325ppm
So there must be something wrong with the first set of reagents that Brett sent me. What I don't understand is why the original test worked well on my tap water and the Standard sample at 200ppm but not on my pool water.

To be sure, I re-did the test with the new kit and got a 250ppm result (10 drops) which could be consistent with manipulator error. Then I performed a high sensitivity test which gave me a 250ppm result (25 drops)

And then I did the test with the original kit and got my yellow compound at 5 drops.

I guess I'll put that kit aside and use the new kit.

Brett I'm happy to send it back to you if you want to test it.

Thank you so much everyone for your help with this one.
Matt any input on why the first kit performed well on Standard solution and tap water but not pool water?

Cheers
 
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Yann,

Not sure. Depends on the chemistries involved and what potential interferences might be in your pool water as well as possibly dealing with a compromised reagent (the indicator dye). I would definitely just discard or return the non-functioning test kit and stick with the one that works.

Does the "bad" indicator dye look different than the new one? Is it clumpy or clinging to the sides of the dropper bottle? Does it look dark blue and viscous?

Reagents can become compromised during storage and shipping, it has been known to happen. So best to just use what you know works.
 
Hi again

"bad" reagents look exactly the same as "good" ones in colour & consistency.

I will run a full pool test when I get home this arvo.

According to my latest results, CYA & CH are on the low end of the recommended range.
Which one should I raise first? Or can I raise both together?
I understand i need to pass OCLT before I raise CYA in case SLAM is needed, then raise CYA in 2 stages over a couple of weeks.
I will be aiming for CYA 70 and CH 300 first and see how the pool is reacting.
I haven't added MA for 10 days and pH is slowly creeping up from 7.4 to 7.6.

Enough guess work for now, let's wait for test results :)

g'day all
 
Glad the second lot worked at least Yann. Please keep using the new one and dispose of the original one no need to return it I have some more here I can look into. I am also confused why it worked on the standard and tap water but not your pool water, I mean I understand what Matt's saying I just also know we'll never really figure out which variable was doing it. I try applying the logical scientific analysis I learnt in uni (psychology and statistics more than wet science) to chemistry but I swear chemistry has its own rules :p it doesn't but it sure feels like it some days. Also the amount of variables involved in pool chemistry can be huge sometimes. Don't get me started :eek:

Buffers are tricky is one of the things I've learnt with making kits. Nicole is often mumbling something about stupid buffers when she's over here working on reagents. Matt do you have a background in chemistry or are you just super into pools? Thank you so much for your help it is much appreciated by me as well. I learn so many things on this forum.
 

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