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Thread: CYA newbie mistake

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    CYA newbie mistake

    Wish the laminated card would say use room temp water for the test, instead of just on the extended directions on this forum. Since it seems to be a major thing.

    Pool is perfect... beyond perfect other than CYA... I thought it was 10, added some to bring it up... read the directions on here, and realized i did it wrong, so got some room temp water, and now the CYA is at 70.

    Guessing it was 50 and not 10 before. Cold water is bad

    Learn from my mistake! I have
    IG, 25k gallons, 20x40 ft, Plaster, Pentair sand filter, variable speed pump, have a well, TF-100 test kit, Speed Stir

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    domct203's Avatar
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    Re: CYA newbie mistake

    How cold is the water, and how much CYA did you add? Are you performing the test outdoors on a bright sunny day with your back to the sun?

    A 40ppm swing from cold to room temperature water seems very excessive.
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    Re: CYA newbie mistake

    Ok. so last year it was around 100 CYA. pool store and me not knowing anything got it up that high.

    So 50 is probably correct as I drained half the pool for winter and let it fill up.

    Water was 59 degrees so not freezing when I first tested it, and the tube filled up and was just slightly cloudy, so i figured 10.

    i added about 20 ppm of cya... so i tested again with the 72 inside temp water and it came out to 70 cya.

    So by all calculations that is correct.

    Just weird that it showed 10 cya at 60 degrees...
    IG, 25k gallons, 20x40 ft, Plaster, Pentair sand filter, variable speed pump, have a well, TF-100 test kit, Speed Stir

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    Mod Squad Texas Splash's Avatar
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    Re: CYA newbie mistake

    We always say that anything less than 30 gets to a point where it is really too difficult to accurately measure. As you know, cold water temps can effect the results, and so does incandescent lighting which is why outdoor (bright) sunlight is so important. Also remember there is about a +/- 15ppm swing in that test due to various conditions, so it's the trickiest to perform.

    Nevertheless, if you're confident of that CYA of 70, all is not lost. Simply adjust your FC accordingly as noted on the Chlorine/CYA Chart and you'll be fine. Over the course of the swimming season, I suspect it will drop a little from standard consumption, splashout, backwashes, etc. You'll be fine as long as you stay close to that chart.
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    Re: CYA newbie mistake

    Yep Just warning other newbs like myself. I am happy it isn't at 100 still...
    IG, 25k gallons, 20x40 ft, Plaster, Pentair sand filter, variable speed pump, have a well, TF-100 test kit, Speed Stir

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    Re: CYA newbie mistake

    PS. The first test was outdoors with bright sun, and the tube filled all the way up, just slightly cloudy could see all the way to the bottom. the next one was indoors with room temp water, but the dot disappeared between 80 and 60... kind of right at 70. using indoor lights and some outdoor through the window. looked the same in both types, and tried it 2 times with same results... so... yea... Meant to test it again yesterday outside, but now I got 2 more days of rain coming.
    IG, 25k gallons, 20x40 ft, Plaster, Pentair sand filter, variable speed pump, have a well, TF-100 test kit, Speed Stir

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    Re: CYA newbie mistake

    CYA should test correctly at 60F. At 40 F, it might test slightly higher, not lower than actual. Did you wait the full time for the sample to develop?

    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 104F, 75F, 60F, and 40F. Only at 40F 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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    Re: CYA newbie mistake

    When I ordered replacement chemicals this spring from TFTestkits.net I also got the CYA standard test solution for $5 and after practicing with it, I now know that I am doing my own tests correctly. The CYA test is the one that I always wondered if I was close or not since it can be very subjective. Now I know that for my eyes, it takes full bright direct sunlight at waist level to read correctly.

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    Mod Squad YippeeSkippy's Avatar
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    Re: CYA newbie mistake

    Quote Originally Posted by slickraft View Post
    When I ordered replacement chemicals this spring from TFTestkits.net I also got the CYA standard test solution for $5 and after practicing with it, I now know that I am doing my own tests correctly. The CYA test is the one that I always wondered if I was close or not since it can be very subjective. Now I know that for my eyes, it takes full bright direct sunlight at waist level to read correctly.

    TFTestkits.net
    Good point, slickraft. I found it helpful when I was new also.

    Yip
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    Re: CYA newbie mistake

    Thought to post this earlier, but forgot. I think I get what was wrong now. I tested it thinking the rain water just mixed with the old water without ever running the pump after winter, and when i opened it. So I guess the new water sat on top of the old so it was 10, then it mixed, and turned to 70 after me adding 20ppm cya.

    Cold water didn't affect it after all after reading some other things as well as what is on this thread.

    So the mistake is mix the water before doing any tests
    IG, 25k gallons, 20x40 ft, Plaster, Pentair sand filter, variable speed pump, have a well, TF-100 test kit, Speed Stir

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    Re: CYA newbie mistake

    Good point. We try to remind folks to always run the pump for at least 15-30 mins prior to any testing and between chemical additions.
    Bob - INTEX 12x24 owner (not setup yet), 'New to me' Kreepy Krauly Sand Shark, Test kit: TF-100 w/Speed Stir

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    Re: CYA newbie mistake

    When I added stabilizer it took at least a day to get an accurate, consistent reading. That's with the pump running 24/7 so I always cringe when people say to test CYA the same day they added it. It's better to wait overnight or a couple of days and get that one right IMHO.
    11k vinyl in ground sport pool with SWG(T-9 cell), 1 hp Hayward Super Pump, Starite 37.5 DE filter, Rheem 20600 BTU gas heater & encapsulated Coverstar auto cover. Taylor K-2006 test kit.

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