TF-100 Chlorine Cylinder Losing Markings?

Katodude

Silver Supporter
Aug 22, 2017
1,244
West Palm Beach/Florida
That off my chest, the light you use to test pool water makes little difference in how much of this or that you dose your pool with. I just like to eliminate variables, however insignificant, when it is just as easy to do so as not. So you... you.... you... weeerrrreeee... were... right. Ouch, that hurt... 😩
I am glad you got past that Fonzi.

And that takes me back to... why I have a pH meter. No color comparisons here.
 

Dirk

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The point I was trying to make about the syringe is you use the markings on the syringe to measure. It's more precise. And inexpensive. Then you are not (in my case) squinting to see some notch on the vial or worrying about over shooting the mark.
Ironic that the markings are wearing off of your syringe, too! ;) I only mention that to keep from hijacking this thread any more than I already have. For me, the syringe or Samplesizer would be a few extra steps, one more thing to rinse, before and after and one more thing to store and replace, etc. I always condemn the use of test strips, while secretly envying their users!! If that 5-in-one-thing worked, I'd be all over that! I did not just say that out loud.
 

Adamphotoman

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Aug 18, 2018
279
Dieppe New Brunswick
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Curious about the syringe. Dirk mentions that it [the syringe] is also loosing it's markings. In this case the marks look like they were applied to the outside of the vial and that they are being scraped off by abrasion as if the syringe was banged up against something -perhaps in a storage case. The TFT-100 vials have the markings on the inside of the sample vials.
My next observation or guess is that one would fill the syringe by first overfilling it and then squeezing the plunger until it meets the desired mark. This means the pool water in the tip is part of the measured volume.

Muggy said "One of the advantages of color comparing (colorimetery) is it doesn't making any difference what the background light is.. at least for doing the K1000 tests."

My background is colour science. In practice, I match colour prints to original artwork, and I have to say that lighting very much matters - at least in my world. I bring that colour matching training to testing pool water. Calibrating equipment also matters;
whether colour monitors, camera sensors or PH meters.:giggle: .
Colour appears different under different lighting. And 2 colours may match under a specific lighting but they may not match under a different lighting. Anyway, that science works with metamerism and is influenced by UV, optical brighteners, and whether certain lighting is missing parts of the spectrum.

Well, as Muggy said, it won't make too much of a difference with the exception of Phenol red matched to coloured paper or plastc.
 
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Dirk

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Adam, I'm surprised to hear the markings on the TF vials are on the inside. Is that true? I thought they were wiping the markings off from the outside. And about the syringe tip, I thought about that, too: what about the amount that remains behind in the syringe that doesn't get squeezed out? I assumed that is compensated for by the position of the markings, as in: once you get the syringe to read 10ml, and squirt that out, you get 10ml, regardless of what remains behind.

Regarding mguzzy's comments on comparing color, I beat him up on that point a bit as well. Theoretically, the lighting wouldn't matter if comparing two objects of the exact same material, both of similar hue and saturation, but that's not what we're doing with the pH test, we're comparing water to plastic, and the lighting would matter, however slightly, because those are two different materials. Similar to the challenges of your work, I'm guessing, in that you're comparing two similar things, but not exactly alike, because they were produced from different materials (Some sort of printer ink vs some sort of paint? Each applied to different kinds of paper/canvas? Something like that?)

Regardless, I think the three of us agree, this is all academic. These testing errors don't come into play while testing pool water because they are not skewing the results enough to make a real-world difference. Especially considering most of the Taylor tests have a margin of error of 10% in the first place! Not to mention we're all dosing bodies of water that are each very much different (size, sun exposure, bather load, building material, etc). We're not making rocket fuel. We don't even need the accuracy required to bake a cake! We're just keeping our pools from turning green!
 
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Adamphotoman

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Aug 18, 2018
279
Dieppe New Brunswick
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Liquid Chlorine
Dirk you are correct on both notes, we are not rocket scientists. However, matching the PH phenol red to the plastic comparator block is much easier against an overcast North sky than with MOST indoor lighting. Lights with a high CRI [Colour Rendition Index] help a whole bunch, but the colour comparison will be much easier with an overcast North sky. Some indoor lighting [incandescent] will mush all the colours together making it difficult to assess small differences. As always daylight type bulbs with a high CRI [anything over 90] will make it much easier to judge.
 
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Dirk

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Indoors, I use LEDs with a "medium" temperature (not too blue, not too yellow) and reflect that off a white card through the comparator, so not the direct LED light. More important (to me) is that I use the exact same light every day. That cannot be done outdoors: weather, time of day, day of year, etc. It's very important to keep track of trends. As in: is my FC dropping? Is my pH rising? Not just: my FC is low today, my pH is high today. And that can best be done using the same light source for each test, day after day. You need daily results for dosing, but trends over time to determine if you've got a problem developing, or if it's time to adjust the SWG for the season, or is CH rising and why, etc. Consistent, repeatable test procedures are more important than precise testing, for both dosing and responding to trends.

The trends part should be obvious, but why would repeatable test procedures be more important for dosing than a perfect FC number? Think about it. We really only need a general idea of the FC to be sure our water is sanitized. You can get that with sloppy testing, because you only need to dose within a range of FC to be sure your water is safe. That's why most of the target values in the FC/CYA chart are expressed as ranges, you only need to get close. What I'm more closely guarding is my minimum FC. And for that, I need accurate repeatable testing. I don't really care that my FC is above the TFP spec or not, because every pool is different. And I don't really need to know that when I test and get FC 3 that it is actually FC 3. I only care that the FC is well above where I know my pool is going to start growing algae (which is 2.5), because that will keep my pool algae-free and safe for swimming. See what I mean? It was my testing proceedure that came up with the 2.5. So as long as I do the testing in the exact same way, I can compare my result against my 2.5 threshold (regardless if either number is "real" or not). And I can't be sloppy about it, because I need to know my numbers are comparable. I may not be explaining that well, but that's what I'm doing.

Now that doesn't apply as well to most of the other tests, the results from which I need to monitor my CSI, for my plaster's longevity. For that number I do need to rely on TFP guidelines and accurate test result numbers, because the end result of my CSI watch won't be evident for another 20 years, and by then I won't be able to do anything about the consequences of poor testing procedures.

Regardless of my ramblings on the subject, it's best to do your testing as precisely as possible, in the same way every day, and arguably one of the most important aspects of precise or repeatable testing procedures is to maintain the markings on your test vial!! :LOL: So stop wipin'em so hard!
 

Dirk

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I have a similar one in my office, but it's about 2' x 2.5'. I don't use it much now, since digital took over and I don't have to view transparencies and film separations anymore. Ha, and I can't be trusted with Phenol Red anywhere near it, that's for sure! But it's how I know how to recognize a decent light temperature for testing when I see it. As I droned on about, I don't need crazy precise test results, and couldn't get them from Taylor reagents even if I did. My LEDs and "reflector card" are more than good enough.
 

Stoopalini

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Jun 8, 2020
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Yah, I cringe when I hear of folks testing in the kitchen (KK, you know who you are!!). I test on my laundry room counter under an LED strip. Very consistent light, good temperature and no shadows. I don't follow the testing-outdoors thing, even for CYA, as I believe a consistent light source is more important. And I almost had a fit when I caught the pool guy I hired to help me with startup throwing his test solutions into my pool. That was the first and last time that ever happened!
Here's my testing location. I know I said the kitchen bar, but it's really a raised bar between the kitchen and living room. It's very convenient, since the sink is right on the other side. I can easily dump my used samples into the sink, and can reach over the bar to quickly rinse items when complete.

I fill that 2 cup measuring container, and use the syringe to fill the test cylinders. I can do a full barrage of tests in about 10 mins this way.

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