Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 5 of 5

Thread: a thought about CYA during a SLAM

  1. Back To Top    #1

    Join Date
    Jul 2013
    Location
    North Canton, OH
    Posts
    192

    a thought about CYA during a SLAM

    I wanted to share an observation from the SLAM I am doing.

    When I started, my CYA (as tested by the pool store) was 65. As the SLAM has progressed, the CYA has dropped to 40 and now 30. I understand that has probably not really happened. Even though I have been filling to replace the water lost from frequent DE backflushing, I don't think it was enough to cause that change.

    It occurred to me that when I started the water was very cloudy. In a typical clear bottled water bottle, the cloudiness was very apparent. And the CYA test depends on the cloudiness of the sample obscuring the black dot (by the way my pool staore does the exact same test). So my conclusion is that when the water is cloudy, as it often is when people start a SLAM, you can't trust the CYA reading which will likely test higher than actual.
    30,000 gal IG 20x40 8ft deep end vinyl liner in NE Ohio DOB Sept 2012
    Hayward 4820 DE filter, Hayward SP2610x15 1.5HP single speed pump
    Hayward H400FDN natural gas heater, Frog min'l/Cl2 system (not in use)
    autocover, Dolphin DX4 cleaner, well water, TF100 test kit

  2. Back To Top    #2
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,928

    Re: a thought about CYA during a SLAM

    Might seem like a logical conclusion, but I would have to disagree. The CYA test isn't based on the cloudiness of the pool water itself, it is a chemical reaction between the water, the organic/inorganic particles remaining, and the reagent we mix in the missing bottle. That's what allows us to find the correct CYA. Others may have a more scientific answer, but that's my lingo. Pool stores notoriously get this test wrong either through improper training, doing the test in a hurry with 10 customers waiting, or because they are indoors using incandescent lighting.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  3. Back To Top    #3

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,077

    Re: a thought about CYA during a SLAM

    It's a good thought but it doesn't work out. Unless your pool is so murky you can't see 3" or so, it will have no effect.

    Simply take a sample of your pool water and put it in the view tube without adding any R-0013. 99% of you will get 0 CYA as a result. In other words, you will be able to see the black dot clearly.

    For those who's pools are the consistency and color of chocolate cake batter (), do the same thing. Now, if you get a CYA of say 30 ppm, you can then add the R-0013 and get a result of maybe 90 ppm, meaning you have 60 ppm CYA
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  4. Back To Top    #4
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,928

    Re: a thought about CYA during a SLAM

    Part of the validation about my comment is the pool store CYA test being different each time you went. That's next to impossible unless a significant amount of water was removed/replaced. Chances are if you took a water sample to 5 different pool stores, you would get 5 different results. That's exactly why we emphasize the TF-100 or Taylor K2006 kits so YOU can be sure the readings are good for yourself.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  5. Back To Top    #5

    Join Date
    Jul 2013
    Location
    North Canton, OH
    Posts
    192

    Re: a thought about CYA during a SLAM

    You could be right Texas. I was just trying to figure out why it had dropped so fast in 3 days.

    FYI, the pool store did the first test, but the other tests were done by the store and me (using the TF100) and our results matched.
    30,000 gal IG 20x40 8ft deep end vinyl liner in NE Ohio DOB Sept 2012
    Hayward 4820 DE filter, Hayward SP2610x15 1.5HP single speed pump
    Hayward H400FDN natural gas heater, Frog min'l/Cl2 system (not in use)
    autocover, Dolphin DX4 cleaner, well water, TF100 test kit

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •