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Thread: New pool (to me), CYA=0

  1. Back To Top    #1

    Join Date
    May 2014
    Location
    Manlius, NY
    Posts
    40

    New pool (to me), CYA=0

    Hi everyone,

    My wife and I bought a house with a 5-year-old pool this winter and we opened it 10 days ago. Around then I found this site, ordered my TF-100, and did some vacuuming and pseudo-blind slamming with bleach, relying on the OTO and pH tests that came with the house. The pool has gone from cloudy green to colorless and almost clear over this time (bottom drain is easily visible but water's a little turbid still), and I did my first TF-100 test this morning. Here are the numbers:

    FC 3.5
    CC 0
    TA 60
    CH 90
    CYA 0
    pH 7.5 or 7.6

    These numbers seem like a pretty good starting point. I was surprised that there was no CYA at all in the pool. The test didn't get even a little cloudy. So my plan for now is to begin to bring up CYA, maybe bring up TA a little bit, and watch to keep the pH where it is in the process. Also, I'm planning to do an overnight FC loss test to see if I need to do a proper slam, now that I can measure FC accurately.

    Here's my biggest question: since I'm at the start of the season and have zero CYA, it seems I could bring it up by adding pure CYA in a sock to my skimmer as recommended, or I could use some trichlor tabs. Each 3" tab adds 1.6 ppm of FC and 1 ppm of CYA, so could buy a bucket of 30 trichlor tabs and a floater and use these over the next month or two, supplementing the FC with bleach as needed.

    Should I consider something like this, or is it better just to use bleach and pure CYA? I guess it depends how much extra FC I'm likely to lose to the sun in the period before CYA comes up, and the costs of the different chemicals. Does anyone have thoughts on this?
    18x36, 19k gal, IG Vinyl, Hayward s244t sand filter, 3/4HP Hayward pump

  2. Back To Top    #2
    Mod Squad jblizzle's Avatar
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    May 2010
    Location
    Tucson, AZ
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    Re: New pool (to me), CYA=0

    Welcome to TFP!!!

    If you never added any stabilizer or used any trichlor or dichlor, then your CYA will be 0.

    It is easier to just use stabilizer and bleach, and usually you want to add at least some stabilizer of the sun will burn all your FC off since it will take awhile to build up the CYA using pucks.

    You could add 20-30ppm of CYA and then use tablets and bleach after that until your CYA reaches your target.
    Jason, TFP Moderator
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  3. Back To Top    #3

    Join Date
    May 2014
    Location
    Manlius, NY
    Posts
    40

    Re: New pool (to me), CYA=0

    Thanks very much. I had assumed the previous owners would have had CYA in the pool, either from tablets or stabilizer. Does CYA decompose over the winter?

    I have no idea how they maintained it, so I had been worried I'd have really high CYA and have to replace water to lower it. I guess I can't complain about having to add some.
    18x36, 19k gal, IG Vinyl, Hayward s244t sand filter, 3/4HP Hayward pump

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