Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 4 of 4

Thread: Ineffective granulated CYA?

  1. Back To Top    #1

    Join Date
    Jul 2014
    Sacramento, CA

    Ineffective granulated CYA?

    I recently decided to increase my CYA from ~35-40ppm to the 50-60 range, because with our always sunny, often hot days, my daily FC loss is a bit higher than I'd like; last year when we bought the house the 80ppm CYA worked better. I understand the tradeoff of higher required SLAM levels, thus decided on 60 as a reasonable compromise level.

    Anyway, I had some unopened HDX granulated stabilizer from last summer, listed as 99.0% Cyanuric Acid. I put 2 pounds in an athletic sock last Wednesday, hung it from a stick near the return, and it was all gone by the next night. I waited a full week (until last night) to test again; result: 35-40ppm, same as before. I have the 50ppm standard solution, and verified again, so I'm pretty sure I'm doing the test right. The weather has been cooler, thus the cover on more, so it's been harder to see if FC usage is down.

    Does it ever take longer than a week to register? Can the CYA either be or go bad to the point that it adds basically nothing? I had only added enough to get halfway to the goal, so I can try another 2 pounds of another brand and even if the first magically appears later it won't be a problem.
    21000gal IG plaster, Sacramento CA area (late 1950s/early 60s)
    Filter: Cartridge, Pentair CCP420 (2014)
    Main pump: Pentair IntelliFlo VS (2015)
    Boost pump: 3/4hp (2011), Polaris 280 cleaner (unknown age)

  2. Back To Top    #2
    Mod Squad woodyp's Avatar
    Join Date
    Apr 2010
    East Texas

    Re: Ineffective granulated CYA?

    If that stuff was sealed, never got wet, it should be as god as day one.
    16x32x52" Steel Cornelius Miramar AGP Vinyl liner 13,100 gal. Buried 2 ft.
    2 Speed Hayward Power-Flo Matrix 85 g.p.m. 22" 250lb. sand filter hard plumbed
    Pool Rover Jr., Pool Blaster Max, Diver Dave TF100 Test Kit/Speed Stir
    Margaritaville Frozen Concoction Maker, Liqour Chiller, & Drink Mixer & Party Tub----Collect 'um all!

  3. Back To Top    #3
    Mod Squad zea3's Avatar
    Join Date
    Jul 2009
    Houston, Texas

    Re: Ineffective granulated CYA?

    The CYA test is rather subjective to read and is accurate +/- 10ppm and you only added enough to raise the CYA by 10ppm. You would have to read the test under the same conditions as the original test to get a comparable reading. With a CYA addition this small it will be difficult to measure with that much precision. Had you added 4lbs and seen no difference I would be more concerned. Go ahead and add the other 2lbs and try and keep the test conditions identical (same time of day, same type and amount of light) as much as possible. You can also pour the test solution back into the mixing bottle and read the test a couple more times and use an average of the tests for the result.
    TFP Moderator
    Helpful links: TF Test Kits,TFP Pool School, PoolMath
    Vogue 21' round AG, Pentair 1 hp 2 speed pump, 36 sq ft DE filter, Hayward S180T 150# sand filter, Houston, Texas
    Love TFP? Become a
    TFP Supporter!

  4. Back To Top    #4

    Join Date
    May 2015
    Ann Arbor, MI

    Re: Ineffective granulated CYA?

    We are still working through balancing our full sun CYA/chlorine levels ourselves but some of the best advice we got was to always do the CYA test holding the view tube at your waist with the sun to your back (so tube is well lit but in the shade). Do the test and record your result, then pour it back innthe mixing bottle and use the same test liquid to repeat a couple more times and use the average as your estimated CYA level. Like zea3 said above. Good luck!
    30,000 gallon in-ground marblelite pool, built ~1968, 18x37
    Hayward Perflex DE Filter, EC-65 (or 75?)
    Hayward Super Pump, 1 HP/230V, 2013
    Aquabot G-Jet, well water, Taylor TF-100 test Kit
    Renovation of marblelite and retiled in 1999

Posting Permissions

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