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

Thread: Are CYA Tests Unreliable?

  1. Back To Top    #1

    Are CYA Tests Unreliable?

    Hey folks,

    Last summer and this summer I noticed that my Chlorine level was diminishing quickly. I was thinking it might be my CYA level causing it. So I tested my CYA using my drop test kit (standard $20 kit from Walmart) that I just bought. It showed next to nothing for CYA (i.e. it was too low to give a reading). So I picked up 6lbs of 100% CYA stabilizer and broadcasted out through the deep end of my 24k gallon pool. I left the pump running all night and 24 hours later I tested it again. Too my surprise though I didn't show any change in reading.

    So, is it that it can take a long time for the CYA to dissolve and change the water chemistry? Or could it be that my new test kit's CYA test was a dud? Or is it that the CYA tests in general are unreliable? Or anything else?

    Thanks!
    18 X 36 In-Ground Vinyl Pool, Hayward 1 HP SuperPump, Hayward SP270T 350lb Sand Filter, CompuPool CPSC48 Salt Chlorine Generator, Hayward H400FDN 400 BTU Natural Gas Heater, 2 returns, 1 skimmer, No Main Drain

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

    Re: Are CYA Tests Unreliable?

    The black dot CYA test is not very precise. The actual level can be noticeably different than what the test reads, but should be somewhere in that general range. Other CYA tests are worse, and can be off by much more.

    Also, CYA does take a long time to dissolve. We recommend waiting a full week after adding CYA before testing the level, to make sure it has all dissolved.
    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

    Join Date
    Jun 2010
    Location
    Rural Southern Illinois
    Posts
    49

    Re: Are CYA Tests Unreliable?

    From my limited experience on here it can take 3-4 days for the CYA to fully dissolve into the water, and up to a week to fully register on the test. So wait another 5 days or so to retest. According to the pool calculator it should be boosted up to 30 ppm. Best of luck!!!
    17100 gallon 27' Round 4' Deep Above Ground Pool
    Hayward Cartridge Filter 1 HP pump 50 GPM flow rate

  4. Back To Top    #4

    Re: Are CYA Tests Unreliable?

    Ahhh....Ok. That makes more sense now. I was definitely scratching my head.

    Thanks guys!
    18 X 36 In-Ground Vinyl Pool, Hayward 1 HP SuperPump, Hayward SP270T 350lb Sand Filter, CompuPool CPSC48 Salt Chlorine Generator, Hayward H400FDN 400 BTU Natural Gas Heater, 2 returns, 1 skimmer, No Main Drain

Posting Permissions

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