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Thread: How to read TFT CYA Test

  1. Back To Top    #1

    Join Date
    Mar 2010
    Location
    Tustin, CA (Orange County)
    Posts
    40

    How to read TFT CYA Test

    Hello,

    Received my new TFTest Kit last week and finally was able to perform my own CYA test. The pool store had tested at 100. Before emptying and refilling, I wanted my own well measured test results.

    When I first tested (Thursday) I felt comfortable with my results (80); but when I returned from vacation today (Wednesday) and retested, the results came in at 90.

    Only acid has been added between those tests so I'm a little confused as to why the CYA would have gone up.

    Wanted to ensure I understood how to read the results just in case the issue lies there. It seems like the test could be read differently depending on one's understanding and visual (20/20) limitations.

    The instructions state: "Keep filling until the black dot in the bottom of the tube is completely obscured."

    Does that mean that the black dot cannot be seen at all, not even a ghosting of it?

    I also thought I read in some posts that temperature of the water and wiping the dropper bottles produces more accurate results.

    Is that correct and can someone expand on the whys behind them if so?

    THANKS!!!
    Tustin, CA (Orange County)
    Curacao Quartz Finish (grey plaster with grey, black, blue & white quartz)
    29k gallon IG
    Pentair WhisperFlo Pump
    Pentair FNS Filter
    Hayward SwimPure T15 SWG

  2. Back To Top    #2

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

    Re: How to read TFT CYA Test

    See the photos in this link on the Taylor website. The black dot is completely obscured and there is no ghosting. The easiest thing to do is to add reagent until you think it might have disappeared, note that reading, add some more and see if it looks more obscured so you don't see the ghosting, then note that reading. It's like other tests where you add more until you don't see any more change. Then, pour from the tube back into the bottle and repeat the pouring into the tube. This way, you can go back and forth without having to use up more CYA reagent so can redo this disappearing act until you feel you've reached some sort of decent reading. With practice, you can narrow things down reasonably well.

    You can get a Taylor R-7065-E 50 ppm CYA standard if you really are concerned about your readings, but this shouldn't be necessary.

    As for viewing conditions, ideally you do the test outside with your back to the sun and your body shading the tube which you hold in front of you looking down into the tube. That is, there should be strong indirect light. If you measure in direct sunlight, your readings will be around 10 ppm too low. If you measure indoors without enough light, your readings will be 10 ppm or more too high.
    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"

  3. Back To Top    #3

    Join Date
    Mar 2010
    Location
    Spring, TX
    Posts
    1,082

    Re: How to read TFT CYA Test

    Out of all the test, this one is very hard to do. From reading on this site you can do the test over and over again with the same sample. Once you pour in the tube and get your results, pour back in the other bottle and do the test again. Maybe this will help you feel better about your results. I usually do this about 5 times and get the same results 3 out of the 5. Just takes practice and patience.
    13,000 Plaster IG Pool approx
    Hayward C5030 Cart Filter
    Emerson 1081 EB653 1.0 HP 1.40 S.F. 3450 RPM
    Pool Calculator, Pool School, TF Test Kits

  4. Back To Top    #4

    Join Date
    Mar 2010
    Location
    Tustin, CA (Orange County)
    Posts
    40

    Re: How to read TFT CYA Test

    Thank you!!!!! I was looking all over for the example picts last night in the wrong place. Thanks for confirming that it needs to be completely gone. I'll also make sure to complete the test in strong indirect sunlight. I was testing under the patio shade. What? It was cooler under there! And a special thanks on reusing the solution to take a few readings!!!
    Tustin, CA (Orange County)
    Curacao Quartz Finish (grey plaster with grey, black, blue & white quartz)
    29k gallon IG
    Pentair WhisperFlo Pump
    Pentair FNS Filter
    Hayward SwimPure T15 SWG

  5. Back To Top    #5

    Join Date
    Mar 2010
    Location
    Spring, TX
    Posts
    1,082

    Re: How to read TFT CYA Test

    Quote Originally Posted by ontherocs
    Thank you!!!!! I was looking all over for the example picts last night in the wrong place. Thanks for confirming that it needs to be completely gone. I'll also make sure to complete the test in strong indirect sunlight. I was testing under the patio shade. What? It was cooler under there! And a special thanks on reusing the solution to take a few readings!!!
    Be careful when you are pouring it back in. Not that it will harm you, but not much room for error.
    13,000 Plaster IG Pool approx
    Hayward C5030 Cart Filter
    Emerson 1081 EB653 1.0 HP 1.40 S.F. 3450 RPM
    Pool Calculator, Pool School, TF Test Kits

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