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Thread: CyA Testing - Age and Eye Sight

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    Join Date
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    CyA Testing - Age and Eye Sight

    The other week I was testing my friends pool he is in his seventies and is a retired fighter pilot, a 747 Captain, and was one of more respected 747 flight trainers for new pilots. He does not wear glasses except for reading. I am in my fifties and do wear glasses, short reading eye sight without them is poor, mid-range is ok, long range average.

    The results were interesting, he said the CyA when the dot disappered was 50 maybe 60, I saw it as around 35 max 40. It lead me to think that this might have something to do with age and one's eye clouding up as one got older. We enlisted the help of our other friend's 14 year old son, he saw it as 30 dead on, as did his brother aged 12, and his father, 38 years old, saw it somewhere around 30 -35, he wears glasses.

    Based on this relatively large differences does anyone know of a better way of testing, and has anyone else noticed this discrepancy?

    Aloha.
    10,000 gal plaster pool,3/4 hp WhisperFlo pump, Sta-Rite Great White GW9500 pool cleaner, Hayward 300 lb Sand Filter
    Use Magenta Stuff for Iron and Silica control.
    Balance: pH 7.7 Cl 7 -8 Alk 70-80 CH 325 CyA 30 in winter - 50 in summer NaCl 1010 TDS 1200

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    Re: CyA Testing - Age and Eye Sight

    Be sure to use the pictures in this link as a guide. There's no question that the test is probably the worst one in the test kits. Though it's pretty easy to get one person to read it consistently, getting the same absolute results from multiple people can sometimes be difficult. Most of the people you had do the test thought the reading was around 30-40 while only one person saw it as 50-60.

    It may be that a calibrated photometric testing unit would do a better job for this particular test, but the test also has some temperature dependence so one has to be careful about that as well. It's unfortunate that there is no "count the drops" test for CYA, but there isn't.

    Richard
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    JasonLion's Avatar
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    Re: CyA Testing - Age and Eye Sight

    Lighting is also important. The test was designed for indirect sunlight, and will give higher readings in typical indoor illumination.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: CyA Testing - Age and Eye Sight

    Good point about the lighting. Taylor Technologies wrote to me that they suggest viewing the tube in front of you facing north so that the sun is behind you (i.e. you are shading the tube) -- that is, using northern sunlight.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: CyA Testing - Age and Eye Sight

    Thank you all for your replies.

    We used the method perscribed by Taylor in the link above, however, we were all south facing into the sun. We will try it again and see what happens.

    Aloha.
    10,000 gal plaster pool,3/4 hp WhisperFlo pump, Sta-Rite Great White GW9500 pool cleaner, Hayward 300 lb Sand Filter
    Use Magenta Stuff for Iron and Silica control.
    Balance: pH 7.7 Cl 7 -8 Alk 70-80 CH 325 CyA 30 in winter - 50 in summer NaCl 1010 TDS 1200

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