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Thread: CYA reading ?

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    maryann79's Avatar
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    CYA reading ?

    The pool is almost three weeks old now, and it's going well. You have been so helpful.

    Early on, we got CYA readings of 50-55. Then, I'd say it read more like 45. We went several days without checking, and now it's more like 35-38.

    My husband and I each independently read it the other night and both got 38 (between 30 and 40, closer to 40 end, that's how we got 38).

    Since the test is so subjective, I find it hard to read. I'm holding it about waist level, in good light, looking down on it, dropping in slowly until the dot is completely covered. I wonder, though, since I know there's a dot there am I going too far in trying to cover it up? Know what I mean?

    Anyway, we either read CYA wrong earlier or are reading it wrong now. Any thoughts?

    The pool looks great, this morning's numbers look good:
    FC--8.5 (same as late last night, passes OCLT)
    CC--0
    Ph--7.6
    (Last night: CYA --35-38,
    TA--80.

    Last night around 6 pm, the FC was 2.5 (CC--0). I seem to have lost a lot of chlorine during the day yesterday, since each night I try and take it to 8-8.5. However, we had a record hot day at 102 degrees yesterday. (Water temp was 92, so you can see how hot.)

    Bottom line, do you think I should add a bit more CYA? I'm wondering if it needs a bit more to slow chlorine loss.
    Pool: 27' x 52" AG, about 16,500K, cartridge filter
    Waterway 175 sq ft 1.5 hp pump 2-speed
    Deck first of June!

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    Re: CYA reading ?

    Yes, push the CYA up just a bit. Holding chlorine during the day is the point of CYA; of course it might be heavy pool usage, lots of sunscreen or hair products, dogs in the pool, dirty feet, etc, using the FC during the day also. Some AGP owners have a small foot bath at the bottom of the stairs to capture grass and dirt (large cat litter box filled with water, easy to dump).

    I try to read the CYA test in the same sort of light each time. Then I pour it all back in to the bottle and fill the bottle to 20, look, then to 30, look, then to 40, look -- to see if my eyes are cheating me. Remember that you are looking for the dot, not the edge of the paper the dot is printed on, sometimes in bright light you will see the floor reflect back the shadow of the paper. You are looking for the dot, not the paper.
    23,000 gallon in ground pool with rock waterfall and spillover spa, Aqualink control system, Polaris 380 cleaner, Purex Triton Clean&Clear Plus cartridge filter. Located in The Woodlands, Texas.

    Pool owner since Nov 2008, Trouble Free since April 2009. Happy to help when I can.

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    maryann79's Avatar
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    Re: CYA reading ?

    We definitely haven't had heavy pool usage, dogs, dirty feet, etc., issues.

    I am dumping what seems like a lot of chlorine into the pool each night. Starting most days around 8 FC, coming home to anywhere between 5 or as low as 2.5 FC. Yet pool is crystal clear and CC is 0. It's been very, very, very hot this summer, however.

    I will increase the CYA. Would there be any benefit to putting some leftover pucks I have into the floating chlorinator to supplement my nightly liquid chlorine and also raise the CYA, or would you just do the CYA sock method? The Ph goes up overnight from 7.6 to 7.8 when I add a lot of chlorine, but it's back to 7.6 by day's end. I guess as bad as I generally know the pucks are, it sounds like in this case they might be a good thing -- adding a little CYA and lowering Ph, and of course boosting chlorine.
    Pool: 27' x 52" AG, about 16,500K, cartridge filter
    Waterway 175 sq ft 1.5 hp pump 2-speed
    Deck first of June!

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    UnderWaterVanya's Avatar
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    Re: CYA reading ?

    I wonder if those of us new to CYA test should post pictures of the test as it looks at various points in the fill process to get a second opinion. Maybe there should be a thread dedicated to this...

    "What's my CYA?"
    Inlaws Pool Boy since June 14th 2012, Pool built ~ 2003, In-Ground, 16'x32'
    13500 gal, Vinyl Liner, Fiberglass Slide, TF-100 Test Kit, Hayward 210T
    sand filter, A.O. Smith 1.5HP main pump motor (C48L2N134C1),
    Hayward SuperPump (model ?), Polaris 380 & PB4 Booster Pump

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    Richard320's Avatar
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    Re: CYA reading ?

    Quote Originally Posted by maryann79
    I will increase the CYA. Would there be any benefit to putting some leftover pucks I have into the floating chlorinator to supplement my nightly liquid chlorine and also raise the CYA, or would you just do the CYA sock method? The Ph goes up overnight from 7.6 to 7.8 when I add a lot of chlorine, but it's back to 7.6 by day's end. I guess as bad as I generally know the pucks are, it sounds like in this case they might be a good thing -- adding a little CYA and lowering Ph, and of course boosting chlorine.
    The big benefit is that you already have the pucks, so there's no out-of-pocket expense!

    At the bottom of the pool calculator, where it says "Effects of Adding Chemicals," see how much CYA an 8 oz puck adds to your pool (Need to have volume entered at the top) then work backwards from that. The equation is (target CYA - current CYA) / (amount each puck adds) = how many pucks you can safely use.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    maryann79's Avatar
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    Re: CYA reading ?

    Thanks, will do!
    Pool: 27' x 52" AG, about 16,500K, cartridge filter
    Waterway 175 sq ft 1.5 hp pump 2-speed
    Deck first of June!

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    linen's Avatar
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    Re: CYA reading ?

    Is that a hose over this side of your pool in your avatar? If you have needed to add a lot of water to your pool lately, that could be a sign of a leak, and leaks lower cya.

    If you use the pucks, keep a close eye on your ph...the pucks lower ph quite a bit.
    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: CYA reading ?

    Quote Originally Posted by UnderWaterVanya
    I wonder if those of us new to CYA test should post pictures of the test as it looks at various points in the fill process to get a second opinion. Maybe there should be a thread dedicated to this...

    "What's my CYA?"
    I would like this... I am having a tough time telling if i see the dot just because I know it's there or its really still visible... Just tested a few hours ago.... Back to the sun, waist high...

    Would love to see others pictures
    ~6500 gal 18' x 52" easy set agp, 7th year
    Intex 2650 sand filter, chlorine
    TF100 Test Kit
    Becoming a TFP lifetime supporter and purchasing the TF100 is absolutely the best money I have ever spent! :-D

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    maryann79's Avatar
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    Re: CYA reading ?

    The hose on the side of the pool in the avatar is from the day we were filling it. I just haven't changed it!
    Pool: 27' x 52" AG, about 16,500K, cartridge filter
    Waterway 175 sq ft 1.5 hp pump 2-speed
    Deck first of June!

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    maryann79's Avatar
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    Re: CYA reading ? PHOTOS ADDED

    I thought I would post some photos of a CYA test I did tonight. I did the best I could with the photos, but it wasn't easy. Autofocus didn't like it, and neither did my eyes manually. From top to bottom, we have CYA 30, 40 and and 50. Let me know what you think.
    Attached Images Attached Images
    Pool: 27' x 52" AG, about 16,500K, cartridge filter
    Waterway 175 sq ft 1.5 hp pump 2-speed
    Deck first of June!

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    Re: CYA reading ?

    My 30 looks like yours .... Will be gone much of the day tomorrow but will try to take some pix in the afternoon when I get back.. Thanks
    ~6500 gal 18' x 52" easy set agp, 7th year
    Intex 2650 sand filter, chlorine
    TF100 Test Kit
    Becoming a TFP lifetime supporter and purchasing the TF100 is absolutely the best money I have ever spent! :-D

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    Re: CYA reading ?

    That black dot should not be visible for correct test result. There are pictures in the sticky for extended test results. You have well below 30 cya
    18x36 inground vinyl lined, Hayward sand filter and tablet chrolinator, approx 18k gallon

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    Re: CYA reading ?

    Quote Originally Posted by spidey07 View Post
    That black dot should not be visible for correct test result. There are pictures in the sticky for extended test results. You have well below 30 cya
    Maybe I don't know what I am doing, but I thought you continue to add fluid until the dot disappears. I can still see the black dot in the photo of "50". Therefore, I would say his CYA is higher than 50? Am I reading this wrong?
    30,000 plaster in-ground pool with spa; 2.5HP single speed Centurion pump; Raypak RP2100 propane heater; Polaris 280 with pump, waterfall with separate pump, Triton II commercial sand filter; TF-100 test kit w/ SpeedStir

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    Re: CYA reading ?

    Quote Originally Posted by Billrector View Post
    Maybe I don't know what I am doing, but I thought you continue to add fluid until the dot disappears. I can still see the black dot in the photo of "50". Therefore, I would say his CYA is higher than 50? Am I reading this wrong?
    You have a good point as I can see the black dot on the 3rd photo as well. If I were running that test, I would have added more until the dot totally disappeared and the tube just looked white. Am I also doing it wrong?
    Home pool: Intex 11,400 gallon AG vinyl pool with sand filter & SWG. Taylor K-2006 test kit - coastal Georgia. I'm also in charge of the Elk's Lodge Pool, which is 55,000 gallons in-ground concrete with sand filter, 2 HP Hayward pump, currently using tri-chlor pucks and cal-hypo system.

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    boston62's Avatar
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    Re: CYA reading ?

    The higher up the tube, and you can still see the dot, then its to low, or none the bottom is 100 to 30 on mine.
    13,000 Gal Pool & Spa
    Jandy Automation /w IAqualink
    Autopilot SWG
    Jandy 2.0 HP VSP, Filter Cartridge
    Taylor (FAS-DPD K-2600, Pool Surface: Plaster

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