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

Thread: How accurate is the CYA test?

  1. Back To Top    #1

    Join Date
    Sep 2011
    Location
    Atlanta Ga
    Posts
    309

    How accurate is the CYA test?

    I've been doing this for over a year and I still have trouble deciding on my CYA level. The black spot on the bottom becomes invisible, then I think I have added too much, then I take out a little and can't decide if I really see a shadow or not. Do other people have this problem? Maybe I am a slow learner, or just old and dumb.

    If 10 experienced pool owners on the forum each tested the same water for CYA, do you think they would all get the same reading? If not, do you think the readings would all be with in 5 of each other? How far apart would you guess the highest and lowest reading would be if we could do this experiment?
    36 x 18 oval pool, inground, plaster pool.
    27000 gallons
    1 hp pump. Sand filter
    Pool built in 1971.

  2. Back To Top    #2
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: How accurate is the CYA test?

    It is +/- 15ppm. Are you pouring the solution back and fork to see if you keep getting the same reading? Or take an average.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  3. Back To Top    #3
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: How accurate is the CYA test?

    I would guess we'd all be within 5 of each other.

    If you want to perfect your testing technique, order the CYA standard solution the next time you order refills. Mix it up as if it were your pool water and see if you get 50. Experiment with the lighting, how far you hold it, anything. Whatever it takes so that you hit 50 +/-every time. Then when you test your water, do it exactly the same.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  4. Back To Top    #4

    Join Date
    Sep 2011
    Location
    Atlanta Ga
    Posts
    309

    Re: How accurate is the CYA test?

    Thanks for the info. I'll try the CYA standard solution.
    36 x 18 oval pool, inground, plaster pool.
    27000 gallons
    1 hp pump. Sand filter
    Pool built in 1971.

  5. Back To Top    #5

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: How accurate is the CYA test?

    The +/-15 ppm is the range Taylor gives and is like a 95th percentile for any of the measured CYA levels. It most likely applies to a high CYA level where 15 ppm isn't a great distance in the tube so its much more likely to have that size of error. For lower CYA levels in the 50 ppm or so range, I'd expect the error to be less than 10 ppm and for experienced people they'll likely be within +/- 5 of their average among them. Once you get used to it, it's a pretty consistent test, assuming you've got reasonably consistent lighting conditions such as standing outside with the sun to your back with your body shading the tube.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

Posting Permissions

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