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Thread: At what water temp is CYA test reliable?

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    At what water temp is CYA test reliable?

    Easy question. I'm opening this weekend to avoid any algae (porus loop-loc cover).

    What are the effects of cooler water on CYA test - does it read low or high? Being precipitate based I would assume it would read high as there would be more precipitate sooner. Secondly I guess if I bring the water inside and get to temp before test I can get a more accurate reading?
    18x36 inground vinyl lined, Hayward sand filter and tablet chrolinator, approx 18k gallon

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    JesseWV's Avatar
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    Re: At what water temp is CYA test reliable?

    Regardless of the temperature of the water in the pool, you could always allow your sample to sit indoors until it warms up to room temperature.
    16k gal, 28'x3.5', Vinyl A/G, 1hp Pentair Dynamo 2-speed Pump, Hayward S160T Sand Filter, Intermatic HB800RCL Digital Timer, Intex 8110 SWG, TF-100 Test Kit, SpeedStir Author: Jesse's Graphical Pool Testing Log

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    linen's Avatar
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    Re: At what water temp is CYA test reliable?

    JesseWV is right on...from the Extended Test Kit Directions:
    If the pool water is below 70 degrees, allow the water sample to warm up to room temperature before continuing.
    Quote Originally Posted by spidey07
    What are the effects of cooler water on CYA test - does it read low or high?
    My recollection is that it reads higher when the water is colder (although not much higher until much colder than 70).
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Mod Squad jblizzle's Avatar
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    Re: At what water temp is CYA test reliable?

    I just answered this same question here:
    viewtopic.php?p=471121#p471121

    I think it reads low when cold.

    Posted from my Droid with Tapatalk ... sorry if my response is short
    Jason, TFP Moderator
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    Re: At what water temp is CYA test reliable?

    Quote Originally Posted by linen
    My recollection is that it reads higher when the water is colder (although not much higher until much colder than 70).
    I couldn't remember what I was recalling so I searched and found this:
    Quote Originally Posted by waterbear
    Precipitation rate is slower but solubility decreases in cold water so if you let it develp to completion it will read high since more will precipitate out.
    And looking at the link to Lamotte's site (could not find anything on Taylor's site):
    Cyanuric Acid (CYA)
    =
    CYA tests are temperature
    sensitive. The best results
    are obtained when sample
    temperatures are between
    70 and 80 degrees. In cold
    water, results may read
    high, while in warm water
    they may read low.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Mod Squad jblizzle's Avatar
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    Re: At what water temp is CYA test reliable?

    Lol. Well, I have no idea, the link in the link that I posted above was to a post from Jason that said it was lower.

    Apparently we need an expert
    Jason, TFP Moderator
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    Re: At what water temp is CYA test reliable?

    Quote Originally Posted by jblizzle
    Apparently we need an expert
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: At what water temp is CYA test reliable?

    The melamine solution that is used in the better tests is at low pH so as to force the maximum precipitation of melamine cyanurate since it is somewhat soluble at pH 7.0 with a solubility of around 20 ppm. There is no question that at colder temperatures it will take longer to precipitate, but as to whether it will be that much more if one waits long enough as to affect the reading, I don't know. Maybe the Lamotte test doesn't lower the pH very much.
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    Re: At what water temp is CYA test reliable?

    Seems like an experiment waiting to happen...though if I did it now, I would have to make up a test solution, since my [s:2bgh3g1u]pool[/s:2bgh3g1u] large test solution is still in the solid phase
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Mod Squad jblizzle's Avatar
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    Re: At what water temp is CYA test reliable?

    Well mine is already at least 75 degrees so that won't help
    Jason, TFP Moderator
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    Re: At what water temp is CYA test reliable?

    If you find yourself in this situation remember that the quickest way to warm (or cool) the water up is to fill up the sink with water that is slightly above your target temp, put the solution in a sealed bottle and drop it in. A water bath will raise the temp far more quickly than the air inside hour house will.
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    Re: At what water temp is CYA test reliable?

    Quote Originally Posted by jblizzle
    Well mine is already at least 75 degrees so that won't help


    Well maybe when I can get a sample, I will start the experiment. In the past I have opened to a cya of close to 0...so my first test will be warmed to RT just to see if I have any to test.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: At what water temp is CYA test reliable?

    I tested mine earlier this year probably temp about 45-50 but I didn't check and it was identical to a test yesterday with the water temp at 66. I bet you will find VERY little difference....within the margin of the test itself, I think.
    Dave S.
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    Re: At what water temp is CYA test reliable?

    Quote Originally Posted by duraleigh
    Always looking to place a bet, I bet you will find VERY little difference....within the margin of the test itself, I think.
    So the water temp isn't all that critical?


    Jeff
    24'x54" AG Morada RTR (by wilbar) 13'500 gal. Hayward Powerflo Matrix 1hp 2 speed. Hayward Perflex EC65 DE filter.

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    Re: At what water temp is CYA test reliable?

    We have had several people having problems with lower than actual readings with cold water because they did not allow enough time for the reaction to run to completion. The standard instructions to mix for 30 seconds is not enough time when the water is cold. You can either mix longer, or warm up the sample to room temperature. My solution is to warm the sample first and then use 30 seconds. Waterbear always recommends allowing two minutes for the CYA test reaction to complete before reading the results, and doesn't bother with warming the sample.
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    Re: At what water temp is CYA test reliable?

    One further question, does it cause errors to wait longer than 30 seconds or 2 minutes even if the water is already warm? Or once the reaction is complete, does the time not matter much?
    Jason, TFP Moderator
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    Re: At what water temp is CYA test reliable?

    Quote Originally Posted by duraleigh
    I bet you will find VERY little difference....within the margin of the test itself, I think.
    I am not taking on the bet, but I will do the experiment if someone else takes the bet

    Quote Originally Posted by JasonLion
    The precision of the test, when done correctly, is around plus or minus 15 for levels up to 90 and plus or minus 30 for levels between 100 and 200. Novices often have problems reading the test correctly, and tend to get higher than actual readings.
    I'll do my best.

    Quote Originally Posted by JasonLion
    We have had several people having problems with lower than actual readings with cold water because they did not allow enough time for the reaction to run to completion. The standard instructions to mix for 30 seconds is not enough time when the water is cold. You can either mix longer, or warm up the sample to room temperature. My solution is to warm the sample first and then use 30 seconds. Waterbear always recommends allowing two minutes for the CYA test reaction to complete before reading the results, and doesn't bother with warming the sample.
    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 . 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 , 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 . 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 ...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 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 . 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 , 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?...
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    linen's Avatar
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    Re: At what water temp is CYA test reliable?

    Of course, if someone else has a pool that is not frozen, with a known cya level, a working speedstir, a decent quick read thermoemter, a fridge, and forgiving significant others...then they could do this experiment (i'm looking at you jbliz )
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: At what water temp is CYA test reliable?

    Good post linen!! It's nice to see a sense of humor here.


    Jeff
    24'x54" AG Morada RTR (by wilbar) 13'500 gal. Hayward Powerflo Matrix 1hp 2 speed. Hayward Perflex EC65 DE filter.

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    Re: At what water temp is CYA test reliable?

    Quote Originally Posted by jblizzle
    One further question, does it cause errors to wait longer than 30 seconds or 2 minutes even if the water is already warm? Or once the reaction is complete, does the time not matter much?
    I know that five minutes is fine and I suspect that you can go longer and still get accurate results. I have never tested beyond five minutes nor heard of anyone who has.
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