At what water temp is CYA test reliable?

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I am also interested in what will happen if you microwave the sample, to speed up the warming. I have a currently unfrozen pool, but unknown CYA level (according to the test I did a few weeks ago, it was less than 30, but I don't think I waited long enough for the sample to warm up.) I am interested in someone doing these tests, so we can know once and for all the effects.
 
Thanks for the help all. Given that I'm opening early with cooler water temps getting a good CYA test is critical. I was around 65-70 at the end of the season. Thank goodness for keeping good logs. It REALLY helps. With any luck I can just take it to shock levels and be done opening, if that's even needed. I don't plan to swim for a while, only to get ahead of the water temps/algae because of my porous loop-loc cover.

The water is still clear and I followed all the advice here on closing as clean as possible and at shock levels so I "should" be good. But there is a ton of pine needles and other "food" that blew in under the cover so I want to get a head start.

JohnN - giving the sample a water bath as mentioned earlier should get you to the temp you want in 5-10 minutes. There's a reason the specific heat of water is 1.
 
I just filled the bottle half way with pool water, brought it inside for an hour so it warmed to at least 70, then added the 013 and did the test after a minute. My CYA was about 5-10 lower doing this, than the test I ran yesterday with the cold water right from the pool.
 
JasonLion said:
Lighting plays a large role. The test is designed to be performed in bright sunlight and will read low if you use indoor lighting.
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I'm sorry for reviving this old thread, but the above statement strikes me as incorrect and I would like to have clarification.

If the CYA test is conducted in weaker lighting than bright sunlight, won't the black dot at the bottom of the test tube disappear earlier to the human eye than in bright sunlight as one is filling up the test tube with the solution? So, won't the test result read higher in low lighting than bright sunlight, if all other conditions and parameters are the same, since the dot seemingly disappears sooner? With the reverse scale of the test tube a lower water level will produce higher level results, won't it?

Or is the CYA test mentioned in this thread a different one than in today's TF-100 test kit?
 
I think it comes back to the fact that the CYA is designed by Taylor to be conducted at waist height, back to the sun in natural sunlight. Once you change one of these variables it can significantly affect your result. I think you'll find this thread useful https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&ved=0ahUKEwiH27n1u5rLAhVGHqYKHQNzDNsQFghBMAU&url=http%3A%2F%2Fwww.troublefreepool.com%2Fthreads%2F99624-Test-CYA-in-the-sun-or-shade&usg=AFQjCNFWVygohCdpYGdwVX4PYNwOdeRPMA&sig2=7OB1s5jgkBWoUtaihHcr5Q
 
https://www.taylortechnologies.com/products_choose_slideshow.asp?KitNumber=K-2006

See this page for video demonstrations of each test. Also note the following:

Do pool or spa water samples have to be at "room temperature" before testing begins?

With one exception, no. Our lab has run the pH, total alkalinity, calcium hardness, free chlorine, and cyanuric acid tests on known standard solutions at approximately 104°F, 75°F, 60°F, and 40°F. Only at 40°F did the CYA standard solution test higher than its actual value (after accounting for test variability). All other tests were unaffected by temperature differences.
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From the Taylor website.
 
Schorschi said:
I'm sorry for reviving this old thread, but the above statement strikes me as incorrect and I would like to have clarification.

If the CYA test is conducted in weaker lighting than bright sunlight, won't the black dot at the bottom of the test tube disappear earlier to the human eye than in bright sunlight as one is filling up the test tube with the solution? So, won't the test result read higher in low lighting than bright sunlight, if all other conditions and parameters are the same, since the dot seemingly disappears sooner? With the reverse scale of the test tube a lower water level will produce higher level results, won't it?

Or is the CYA test mentioned in this thread a different one than in today's TF-100 test kit?
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Schorschi,

What I believe occurs is that when you mix your pool water to produce the CYA test, particles are dispersed throughout the liquid. These particles are very reflective to light. If you look at the black dot during a low light situation, the dot will remain visible longer due to the particles having less light to reflect (i.e., light to obscure the dot). When you add more light to the test, the particles suspended in the liquid reflect that light more readily and obscure the black dot sooner.

You can prove this to yourself by doing the test indoors just until the dot is still barely visible. Then take the tube outside into the bright sunshine and look for the dot. You will notice that the dot that was barely visible is now completely obstructed.
 

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linen said:
I am not taking on the bet, but I will do the experiment if someone else takes the bet :twisted:

I'll do my best.

Here is a start at a proposed test method...

I will need to do this in the dead of night so my beautiful wife doesn't see me using her fridge :taped: . First, I plan on removing the milk jugs and stuff to make room in the fridge. Next I will attempt, again under the cover of darkness :batman: , to draw water from pool using a tube the gets down near the bottom of pool between ice and wall to retrieve sample. I will bring the sample indoors and place it in the fridge. I will also place the mixing bottle, view tube and R-0013 into the space I have created in the fridge. I will fill the mixing bottle to the proper level with the pool water. Then I will let all of that stabilize in the fridge for about an hour...the fridge is at ~38F. Next, using insulating gloves, I will dispense the proper amount of R-0013 into the mixing bottle while keeping all components inside the fridge compartment :rambo: . Here is where I have a bit of a challenge as my speedstir's circuit board saw too much water and no longer works correctly :cry: ...but I was thinking of putting in a clean (small) stir bar into the mixing bottle and letting is spin for a bit...maybe I can steal a stir plate from work this weekend. My thought was letting it mix for 5 minutes. The next part is also tricky, since I must do this in the dead of night :batman: and in the fridge, I was thinking of finding a flashlight app for my phone that will simulate outdoor light. I think I will place the tube on white paper and have the phone light the sample from one side. Then I will dispense the test solution into the tube until the dot disappears. At that moment I will test the temperature with a quick read thermometer and then note the value. I think I will repeat this 3 times by pouring the sample back into the mixing bottle and always handling everything with insulating gloves. After getting 3 measurements at ~38F (or whatever the quick read thermometer tells me), then I will allow the pool water sample and all the equipment warm to room temperature. We keep our house at ~65F in the winter, so I might need to bump up the temp to 70+...again, must do this at night as to not be observed :batman: . I will repeat the test (3 times) also mixing for 5 minutes and attempting to simulate the same lighting conditions as in the fridge (this will be challenging...maybe I need to go back into the fridge just when I fill the tube to simulate the same lighting conditions, of course still measuring temperature with the quick read thermometer). I am also considering corrupting one of my sons :twisted: , and getting two different eyes looking this giving us two sets of numbers. I better look to see how much R-0013 I have...

Thoughts?...
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Funny post, except The part about no more stir stick was sad ?
 
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