Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 9 of 9

Thread: CYA natural reduction rate

  1. Back To Top    #1

    Join Date
    Jun 2014
    Location
    Dallas TX
    Posts
    9

    CYA natural reduction rate

    I'm in the middle of reducing my CYA to appropriate levels. I did a partial drain and refill which brought it from around 120 to 100, then I used Bio-Active which brought it down to 60. Neither of these methods are fun... drain and refill is expensive and wastes my DE. And Bio Active is expensive and has to be used with FC under 2, meaning algae is all but guaranteed.

    I'd like to have CYA between 40-50. How long will it take, roughly, for this to happen naturally (evaporation and refill, and rain water dilution)? Or should I bite the bullet and do another drain?
    40,000 gallons
    DE 60 sq. ft.
    In-ground
    Plaster

  2. Back To Top    #2
    Patrick_B's Avatar
    Join Date
    Jun 2011
    Location
    Midland TX
    Posts
    15,001

    Re: CYA natural reduction rate

    Bite the bullet. We have seen so little success with Bio Active, it isn't worth mentioning. Yours is the most I think we've heard of. Natural Cya reduction happens over time, usually in Algae laden pools over the winter. If you want it down, drain is the only viable solution within reasonable costs. I suppose you can try the risk of more Bio Active, but it's up to you.
    TFP Moderator
    Essential Links:
    ABC's Of Pool Chemistry, Test Kits, SLAM Your Pool
    28K Gal IG FreeForm, CLI Quartz, Pentair 36"SF & VS Pump, Dolphin M5, Rheem

  3. Back To Top    #3
    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Location
    Columbia, SC
    Posts
    8,495

    Re: CYA natural reduction rate

    If water is available and there are no other reasons not to such as extremely high water cost, restrictions on water use, or the reverse a high water table that makes draining potentially damaging do the drain & refill.

    Your 40 point reduction in CYA with BioActive is one of the best outcomes we have seen here. Most have had zero reduction.

    I started at over 200 and took over 18 months to get it down through aggressive back-washes, multiple small drain and refills as well as harvesting rainwater from roof gutters.

    CYA naturally goes down a few ppm a month. Evaporation does not count, as the CYA stays behind when water evaporates. Only when bulk water leaves the pool by either being pumped out or splashed out does CYA go down.
    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

  4. Back To Top    #4
    JayBauman's Avatar
    Join Date
    Sep 2014
    Location
    Katy, TX
    Posts
    617

    Re: CYA natural reduction rate

    Quote Originally Posted by jmarsden26 View Post
    I'd like to have CYA between 40-50. How long will it take, roughly, for this to happen naturally (evaporation and refill, and rain water dilution)? Or should I bite the bullet and do another drain?
    If Texas keeps getting all of this rain, you'll be at your target CYA level in about 2 weeks by the ever-popular "dilution via precipitation" method.

    Ok, all joking aside....if you're at 60 now and you want to get down to 50, I'd do nothing. You're already close to your target (and well within the error bars on the measurement). Check it again in a month, or sooner if it rains again, and see where you are.
    23' x 37' IG 18.5k gallon SWG w/ raised spa, Build Thread -->Here
    Wet Edge® Pearl Matrix®, Hayward® SwimClear™ 525 ft², Hayward® Goldline Controls® PS-8
    4x Hayward® TriStar™ pumps, Paramount PCC2000® ICS, TF-100 w/Speedstir

  5. Back To Top    #5
    Texas Splash's Avatar
    Join Date
    Jun 2014
    Location
    South-Central Texas, Marion/San Antonio
    Posts
    12,975

    Re: CYA natural reduction rate

    I have to agree with JB on that one. The Texas sun, when we're not flooded with rain, has been killing my FC. I've been letting my CYA creep-up close to 50 now to preserve FC. I might even go a tad higher.
    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!

  6. Back To Top    #6

    Join Date
    Jun 2014
    Location
    Dallas TX
    Posts
    9

    Re: CYA natural reduction rate

    Thanks for advise. I did another small drain this weekend with a rain coming Sunday. Now happily at 45!!

    I haven't read many other bio-active results but I think mine was successful because I had basically 0 FC the whole 7 day period. The water got cloudy and algae began to form, so definitely not a perfect solution.
    40,000 gallons
    DE 60 sq. ft.
    In-ground
    Plaster

  7. Back To Top    #7
    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Location
    Columbia, SC
    Posts
    8,495

    Re: CYA natural reduction rate

    Quote Originally Posted by jmarsden26 View Post
    I haven't read many other bio-active results but I think mine was successful because I had basically 0 FC the whole 7 day period. The water got cloudy and algae began to form, so definitely not a perfect solution.
    I think you are correct on the "0" FC being a factor, but I think there are other variables yet to be identified that allow it to work or not work.

    If you want to look at them, we put all the BioActive threads in the forum The Deep End
    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

  8. Back To Top    #8

    Join Date
    Mar 2015
    Location
    Sugar Land , TX
    Posts
    388

    Re: CYA natural reduction rate

    JB is funny " If it rains again " . Never thought I would say this but STOP RAINING ALREADY!
    8500 gallon IG Pebble Sheen with Spa. 3hp Pentair VS Intelliflo ( pool ), 3/4 hp WhisperFlo ( water feature ),Pentair Racer, 400K Pentair heater, Pentair 500sqft Cartridge filter, EasyTouch 8, Stenner 45mp2 15gallon wired to ET8

  9. Back To Top    #9
    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Location
    Columbia, SC
    Posts
    8,495

    Re: CYA natural reduction rate

    Maybe it's time to pump TX water to CA
    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

Posting Permissions

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