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

Thread: CYA question

  1. Back To Top    #1

    Join Date
    Jul 2016
    Location
    Hudson/New Hampshire
    Posts
    23

    CYA question

    This has probably been asked, but does CYA ever lower on it's own, or once I reach the level it will maintain? Does anything effect CYA like evaporation causing it to concentrate or adding water/rain diluting it?
    Hudson New Hampshire
    11000 gal AG 21ft by 52 inch deep round since 7-1-16
    Clearwater II 2hp/2sp cartridge filter
    Well water to add to pool but filled with plain water truck
    TF-100

  2. Back To Top    #2
    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Location
    Columbia, SC
    Posts
    8,494

    Re: CYA question

    CYA naturally degrades very slowly, maybe a few ppm per month. Splash out of the pool is the biggest loss, so,if there are lots of kids, maybe a swimming dog or two - you will see loss there.

    You have it correct, if water evaporates the CYA goes up but right back down when you add water back.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

  3. Back To Top    #3

    Join Date
    Jul 2016
    Location
    Hudson/New Hampshire
    Posts
    23

    Re: CYA question

    Thank you very much. It's slowly starting to click! Best resource ever
    Hudson New Hampshire
    11000 gal AG 21ft by 52 inch deep round since 7-1-16
    Clearwater II 2hp/2sp cartridge filter
    Well water to add to pool but filled with plain water truck
    TF-100

  4. Back To Top    #4
    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Location
    Columbia, SC
    Posts
    8,494

    Re: CYA question

    Quote Originally Posted by shandoug View Post
    Best resource ever
    Thanks!

    I will just add that TFP is staffed by volunteers and folks like you keep the lights on with donations

    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

  5. Back To Top    #5
    Pool Tool's Avatar
    Join Date
    May 2014
    Location
    Western Chicago Area, IL
    Posts
    754

    Re: CYA question

    CYA testing is a little tricky. Try to recreate the same environment for testing, i.e. same sunlight, back to sun, vial at waist level, vial held with two fingers at the top, etc. If it was not bright out or you held the vial in direct sunlight it will give you a lower reading. This may not be the case but it could be skewing the numbers. Without water replacement your CYA should not change that much.
    16' x 32' (21100 gal), vinyl, 1.5 hp Hayward SuperPump,
    Tagelus TA60/60D Sand Filter, Raypak 399K Digital Heater, TF-100

Posting Permissions

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