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Thread: Please check my Math, Testing Method (and perhaps Sanity) please?

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    Please check my Math, Testing Method (and perhaps Sanity) please?

    Hi All,

    19k gal IG Vinyl. Closed last year (covered), opened this year to green swaped.

    Cleaned bottom (even though I cant see it) to remove sludge (not a ton, but decent amount). Vacuuming or sweeping every day.

    CYA at zero and remaining there despite having added 20 lbs.
    PH 7.4
    Ammonia (as tested with my aquarium kit) only .25 to .5 ppm.

    Now the fun math/testing method part:

    Over the past week, I've added about 46 gallons of 12.5% liquid shock.

    To get my TC and FC, I've had to do the following:

    10ml sample. Should turn pink with 1 or 2 dippers of DPD Powder. Takes 4 dippers to get it to turn (and stay) pink. Because TC is so high?

    Added 160 drops of R-0871 before it turned clear (so 80 ppm TC).

    Normally add 5 drops of R-0003 to get it to turn pink again, but had to add 10 to 15 drops to get it to turn pink (because I added so much R-0871?)

    Few drops of R-0871 and it went back to clear (so it would appear essentially no FC).

    Is my usual way of testing with these reagents off due to the super high TC?

    Even at 80 ppm TC, should I keep sending it higher until I can get a reasonable FC reading? Or should I wait for TC to come down some?

    19,000 IG Vinyl, sand filter, liquid chlor, 1HP pump

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

    Re: Please check my Math, Testing Method (and perhaps Sanity) please?

    It should only take 1-2 scoops of powder even for very high FC levels. With no CYA, you should only be targeting a FC of 10ppm, so it should not be very high.

    BUT, looks you are are adding nuclear amounts of bleach which is NEVER a good idea. The FAS-DPD is good up to 50ppm.

    Do NOT add any more bleach to your pool until you learn how to follow the SLAM Process correctly and safely.

    Do you have an OTO chlorine test? (yellow color matching?)
    What test kit are you using?
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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  3. Back To Top    #3
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Please check my Math, Testing Method (and perhaps Sanity) please?

    I think you have what the FAS-DPD test is testing mixed up. First you add R-0870 powder, then the number of drops of R-0871 counts FC. Then 5 drops of R-0003, then drops of R-0871 count CC.

    Above you were saying TC and FC, which is incorrect.

    If five drops of R-003 does not turn the sample pink, there is no CC and the test is over.

    When the FC level is exceedingly high it can take quite a few scoops of R-0870 powder. However as FC goes up you need to do the test more and more quickly. The total amount of time you have to do the test is limited. The more drops total there are going to be the more quickly you need to add each drop. Things start to get tricky as FC gets into the 40s, and anything over 50 is gets really problematic. If you don't add drops quickly enough you can get a false high reading.
    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

  4. Back To Top    #4

    Re: Please check my Math, Testing Method (and perhaps Sanity) please?

    UGHGHGHHGH!!!!!! You hit the nail on the head JasonLion. I was completely reading it wrong. All this time I thought I had astronomical TC and zero FC. I had read that in that case I need to just keep adding bleach until I got 5 to 10 ppm FC.

    Ok, whose the noob? *This Guy*


    Well, thank you all. Guess nothing to do now but wait and hope for lots of sun. Any maybe drain some off to dilute.
    19,000 IG Vinyl, sand filter, liquid chlor, 1HP pump

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