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Thread: New K-2006 user - reason for CYA discrepancy?

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    New K-2006 user - reason for CYA discrepancy?

    Hi folks,

    I'm new to the method this year. I bought myself a Taylor K-2006 and am starting the process. My pool water is nice, but I am starting to get some plaster corrosion.

    Setup: Plaster, 24000 gal. Been alternating b/w dichlor and cal-hypo over the years, and I've been using trichlor tabs + dichlor so fa this season.

    Levels with the Taylor look like:
    TA - 60
    pH - < 7.0 (way less .. base demand takes 15 drops to get to 7.4)
    CH - 350
    CYA - >> 100. (I can only get < 1cm in the test tube before losing the black dot).

    I also have some Hach Aquacheck 7 strips. They read approx like this:

    TA - 70
    pH - 6.4-6.6
    CH - 350
    CYA - 30-50.

    My question is, why such a discrepancy in the CYA readings? Is it a known issue with the strips, the Taylor, or is my extremely low pH affecting one of the tests?

    Thanks much.

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    JasonLion's Avatar
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    Re: New K-2006 user - reason for CYA discrepancy?

    Welcome to TFP!

    Believe the Taylor CYA test. Test strips are not reliable, especially for CYA for which they are often wildly wrong (as they are here).

    We do not recommend using dichlor for this exact reason. Dichlor adds lots of CYA and will rapidly drive your CYA level way out of range.

    You are going to need to do a significant amount of water replacement at this point to get your CYA level down to something reasonable.
    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: New K-2006 user - reason for CYA discrepancy?

    You confirmed my suspicions.. unfortunately

    Do you recommend treating the TA/pH before or after dealing with the CYA? Is there any interaction or dependency?

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    JasonLion's Avatar
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    Re: New K-2006 user - reason for CYA discrepancy?

    I would raise the PH at least to 7.0. PH below7.0 can damage the pool.
    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: New K-2006 user - reason for CYA discrepancy?

    It always amazes me just how bad test strips can be, yet still sold as useful tools. Thanks to what I learned here I don't even use them to test my aquarium pH any more.

    As Jason said, get your pH up, it is too acidic right now. With the taylor you only have enough reagent for a few CYA tests. You may want to do a dilution test to get a good goal for your drain. Use 50% pool water and 50% tap water and run the test. Hopefully you get a reading, double that and you get an appox. CYA level to work with.

    JD - 28' Round Above Ground Pool, 17,000 Gallons. Dual speed Jacuzzi pump with cartridge filter. Dual speed 1 HP pump, Hayward S210T sand filter
    Pool School - PoolMath - HIGHLY Recommended Test Kits

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    Re: New K-2006 user - reason for CYA discrepancy?

    Great information. I'll spend some time getting the pH up, and then start on the dilution cycle for the CYA. And the strips go in the garbage. Thanks for the advice.

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    Mike59's Avatar
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    Re: New K-2006 user - reason for CYA discrepancy?

    Quote Originally Posted by gwaldron View Post
    Great information. I'll spend some time getting the pH up, and then start on the dilution cycle for the CYA. And the strips go in the garbage. Thanks for the advice.
    Welcome to the site. I am also new here and have had similar issues with very high CYA. Before coming here my strips read around 50 for CYA. Two different pool stores said 100. I drained 1/3 of my pool water and went back to the pool stores. Both readings remained at 100.

    I then received my test kit and the first reading showed it was over 100. So I dumped 7ml and replaced with tap water and doubled the results. My readings were 180!!! This told me my original readings must have been over 200 and that pool stores only read up to 100. I've had this issue for the last couple of years...but the pool store kept saying my water was "dead" because it was so old. But they kept selling me cholorine granulars and pucks, both with stabilizer. Insane!

    I then drained probably 2/3 of my water (10,000 gallons) so that water was a foot on the shallow end and refilled.
    My CYA is now 80. I'd have to drain 1/2 of my pool again to get that down to 40. But I'm going to work with 80 for now.

    So just be aware that you will need patience getting the CYA level down, but it has to be done.
    Its been a pain, but I'm looking at this as a great learning experience and know the future will be crystal clear!

    Good luck and keep us up to date on your progress.
    16K gal, IG Vinyl, Hayward DE Filter EC-65, 3/4 HP pump, Raypak R266A Gas Heater, Hayward Chlorine Feeder (Retired), Dolphin cleaner. K-2006 w/ Speedstir.
    Pool 18yrs - Liner 14 yrs

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