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Thread: Need help with CYA for startup

  1. Back To Top    #1

    Join Date
    Jul 2011
    Location
    Central VA
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    14

    Need help with CYA for startup

    Help! The water truck was here last Wednesday and I diligently followed the instructions in the article "Beginners Guide for Seasonal/Temporary Pools". Added enough chlorine to get it to 6 ppm the first night, and jumped in. After our first swim I added dichlor as directed for the four days. (Wed, Thurs, Fri, Sat). A week later and still no CYA reading at all. The test solution doesn't even begin to cloud up. It's good that my water's clear and all, but it sure would be nice if it clouded up when I tried to make it cloudy! I'm thinking there's some in there, as I'm not losing all of my chlorine during the day (pool is in direct sunlight late morning into early evening). This morning was the first time my FC dropped to below 4, and I've not added anything since Saturday.

    My numbers from 5:15 am:
    FC = 2 (added bleach before I left for work this am.)
    CC = 0
    pH = 7.5
    T/A = 70
    CYA = 0
    CH = 50

    Big question -- do I stop on the way home and get CYA, or is there something else I'm missing?
    Central VA
    My 'disposable' pool -- 7600 gal 18' round AG Intex Ultra Frame, Intex sand filter
    Took it down the first year, but it has been up year round for three years now
    Was really hoping last winter would have done it in so I could justify an upgrade!

  2. Back To Top    #2
    JasonLion's Avatar
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    May 2007
    Location
    Silver Spring, MD
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    37,879

    Re: Need help with CYA for startup

    Welcome to TFP!

    There are basically two possibilities. Either the CYA test is not working, or the CYA level is just below the threshold that the test can detect. Depending on which CYA test you are using the detection threshold might be 30 ppm or higher.

    Which CYA test are you using?
    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

  3. Back To Top    #3
    Puffin's Avatar
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    Jul 2010
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    Metro Atlanta, Georgia
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    Re: Need help with CYA for startup

    Sometimes dichlor is sold in lesser concentrations. What does the package you're using say about the concentration of dichor. The seasonal pool guide is expecting the 99%+ stuff.

    I found this out the hard way, when I was first opening my pool. I couldn't figure out why my CYA wasn't going up and chlorine seemed low. The Aquachem stuff I was using was like 40% or 50% dichlor.
    19,600 gal, Vinyl, Grecian L, StaRite Dura-Glas 1 HP pump, 3/4hp booster, Pentair Clean and Clear 420 Cartridge filter
    The Pool Cleaner 4x, PoolSkim

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    Join Date
    Jul 2011
    Location
    Central VA
    Posts
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    Re: Need help with CYA for startup

    Thanks for the quick responses, guys. CYA test is that which comes in the TF-100 test kit. Don't know the concentration of the dichlor off the top of my head, and I've thrown out the packaging already. I'll slide by Lowes and check it on the way home.
    Central VA
    My 'disposable' pool -- 7600 gal 18' round AG Intex Ultra Frame, Intex sand filter
    Took it down the first year, but it has been up year round for three years now
    Was really hoping last winter would have done it in so I could justify an upgrade!

  5. Back To Top    #5
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Need help with CYA for startup

    The CYA test in the TF100 can report levels as high as 20 as if they were zero. The seasonal pool instructions are designed to raise CYA to 30, but it wouldn't take too large of an error for CYA to be under 20.
    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

  6. Back To Top    #6

    Join Date
    Jul 2011
    Location
    Central VA
    Posts
    14

    Re: Need help with CYA for startup

    Sooooo - I assume I move really conservatively here? And tell the calculator it's at 20, just to be safe?
    Central VA
    My 'disposable' pool -- 7600 gal 18' round AG Intex Ultra Frame, Intex sand filter
    Took it down the first year, but it has been up year round for three years now
    Was really hoping last winter would have done it in so I could justify an upgrade!

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