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Thread: CYA quandry

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    mariane's Avatar
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    CYA quandry

    I have been testing the CYA levels of the pool water in several conditions and each time have gotten a different number.
    On a cloudy day: 35
    In shade: 40
    In full sun with the sun at my back: 50
    I'm interested in why this happens and in which condition is best to test CYA.
    Thanks for your help.
    16 x 28 Doughboy Mystic Garden AGP with 7' deep end (used expandable vinyl liner) ~11,800 gals. Deep end main drain. Thru-the-wall skimmer, one return at deep end. Media Master 150# sand filter. Doughboy PowerPak II pump, 1 hp. Pentair MinimaxCH 150m natural gas heater. Polaris 65 when it feels like working . TF-100 test kit. No longer 'pool stored' 5 years and counting. In sunny but fickle metro-Detroit.

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    Re: CYA quandry

    full sun with sun to your back.

    Pool School - CYA

    Stand outdoors with your back to the sun and hold the view tube at about waist level. If sunlight is not available, find the brightest artificial light you can.
    Built in 1957 44,000 gallon in-ground, Wet Edge Primera Stone in Sky Blue, Intelliflo VF Pump, 600 lb. Pentair Triton II TR-100 Sand Filter, CircuPool RG 60 Plus SWG, TF-100 test kit
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    mikemass's Avatar
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    Re: CYA quandry

    I find the CYA test to be very subjective as to determining exactly when the black dot "disappears". I have the same issues in any light.
    25 + year pool owner. Current pool (going on 11th year) - 38K gallon in ground Gunite/White Plaster, Spillover Spa, Hayward Cartridge Filter, Hayward 450k BTU NG Heater, Hayward Goldline Aqua Logic control with T-Cell-15 Salt Water Cell, Dolphin Explorer.
    You Need: Bleach, a A Test Kit & a Bookmark to "Pool School". Now what's your question?

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    Re: CYA quandry

    Here's the main thing. Are you in the 30-40 range, or 70-80. See what I mean?
    Built in 1957 44,000 gallon in-ground, Wet Edge Primera Stone in Sky Blue, Intelliflo VF Pump, 600 lb. Pentair Triton II TR-100 Sand Filter, CircuPool RG 60 Plus SWG, TF-100 test kit
    If TFP has helped you, please click to SUPPORT TFP!

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    Frankhugus's Avatar
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    Re: CYA quandry

    Quote Originally Posted by mikemass View Post
    I find the CYA test to be very subjective as to determining exactly when the black dot "disappears". I have the same issues in any light.
    Me too. Having high CYA I want to keep "seeing" the dot and that might influence the result.
    14,000 Gal, InGround, Spa Attached, Satin-Matrix Northshore Tahoe Pebble-Tec, Remodel 6/15, Taylor K-2006 Kit, Pentair IntelliFlo Variable Speed Pump, Polaris 280 Sweep, Jandy CL460 Cartridge Filter, Solar Heated. Taylor K-2006 Test Kit

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    mariane's Avatar
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    Re: CYA quandry

    Thanks RobbieH. In all the past threads I've read, the "shade" numbers should be higher than the "full sun" readings but mine are backwards.

    We do a partial drain in the fall for the winter deep freeze and then refill in the spring. Our tap water does not have any CYA in it. Since full sun number is 50, and I have not added any CYA this year, the levels must have been very high last year which I don't remember that being the case.

    That would explain the SLAM taking longer than usual. I was going by the "35" reading and still have slightly cloudy water. The FC levels drop 4 numbers every night.
    16 x 28 Doughboy Mystic Garden AGP with 7' deep end (used expandable vinyl liner) ~11,800 gals. Deep end main drain. Thru-the-wall skimmer, one return at deep end. Media Master 150# sand filter. Doughboy PowerPak II pump, 1 hp. Pentair MinimaxCH 150m natural gas heater. Polaris 65 when it feels like working . TF-100 test kit. No longer 'pool stored' 5 years and counting. In sunny but fickle metro-Detroit.

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    JoyfulNoise's Avatar
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    CYA quandry

    Full sun, tube waist high in the shadow cast by your body. You MUST make sure that your hand is in no way blocking the frosted plastic of the tube. If you are using the K-2006 with the large block comparator then you hold the block by the pH side. If you are using the narrow tube with the TF-100, then you "pinch" the top of the tube between two fingers and keep your hand and fingers flat and extended (like how to hold a cup of tea in proper British royalty fashion). Also, as you add drops, try to look away every so often to relax you eyes - staring intently into the tube can make the dot appear to be there. As well, keep the tube vertical - the curvature of the water at the meniscus can make the dot seem to be there.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    mikemass's Avatar
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    Re: CYA quandry

    I don't "pinch" the tube. I place it on a white piece of paper and let it stand on it's own. Is this wrong?
    25 + year pool owner. Current pool (going on 11th year) - 38K gallon in ground Gunite/White Plaster, Spillover Spa, Hayward Cartridge Filter, Hayward 450k BTU NG Heater, Hayward Goldline Aqua Logic control with T-Cell-15 Salt Water Cell, Dolphin Explorer.
    You Need: Bleach, a A Test Kit & a Bookmark to "Pool School". Now what's your question?

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    lindaspoolboy's Avatar
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    Re: CYA quandry

    i use this:
    TFTestkits.net (R-7065 CYA Standard Solution)
    to help develop a gut feel for what it means for the black dot to "disappear".
    29,000 gallon vinyl IG, Hayward 1.5hp Pump, DE Filter.

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    JoyfulNoise's Avatar
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    Re: CYA quandry

    Quote Originally Posted by mikemass View Post
    I don't "pinch" the tube. I place it on a white piece of paper and let it stand on it's own. Is this wrong?

    No. As long as you maintain a good eye-tube distance and the lighting is bright and indirect.

    Quote Originally Posted by lindaspoolboy View Post
    i use this:
    TFTestkits.net (R-7065 CYA Standard Solution)
    to help develop a gut feel for what it means for the black dot to "disappear".
    New TF-100 kits will now be sold with a small amount of that standard solution to help new TFP users get used to the test.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    mikemass's Avatar
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    Re: CYA quandry

    I got to get some of that R-7065 to see what it really should look like. Thanks for that.
    25 + year pool owner. Current pool (going on 11th year) - 38K gallon in ground Gunite/White Plaster, Spillover Spa, Hayward Cartridge Filter, Hayward 450k BTU NG Heater, Hayward Goldline Aqua Logic control with T-Cell-15 Salt Water Cell, Dolphin Explorer.
    You Need: Bleach, a A Test Kit & a Bookmark to "Pool School". Now what's your question?

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