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Thread: FC Testing Q

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    Tom Tank's Avatar
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    FC Testing Q

    New pool owner and recent convert to the TFP method. Using the TF100 test, my CYA=100, so I know I need to drain water, but really don't want to do that until the season is over. So I am left with maintaining a pretty high FC between 7-12. My questions are: Because my FC level needs to be higher than 5, do I have to use the FAS/DPD daily? Is there a way to dilute the water and use less of the drops or use the OTO test for chlorine that is higher than 5. Thanks.
    22,200 gal, IG Vinyl 3.5' - 8.5', Haywood s240 Sand Filter, Polaris 180
    manually chlorinate, 2 skimmers - 1 main drain - 3 returns plus waterfall feature
    TF-100 test kit, pool in sun ~10am - 5pm

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    Smykowski's Avatar
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    Re: FC Testing Q

    Just use the FAS-DPD. I've been on TFPC for 3 years and I've never done an OTO test. When you're wrestling with a CYA that high, you really need accuracy and precision in that upper range.
    33' round, 23,000 gal AG vinyl , 1HP 2spd PowerFlo Matrix downsized with 3/4HP impeller (X2), Hayward S180T 150# sand filter (X2), Hayward H250 NG heater Pool Store year 1 - $850 for 2 months; Pool Store year 2 - $440 for 2 months, TFPC year 1 - $170 for 4 months; TFPC year 2 - $95 for 4.5 months
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    Tom Tank's Avatar
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    Re: FC Testing Q

    Is there a way to dilute the water for testing for FC? I am in the middle of a SLAM and have to maintain a FC=39.

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    Re: FC Testing Q

    You'd have to use distilled water, tap water will have FC in it.

    Are you sure you are at 100? Have you tested CYA with a 50/50 tap/pool water mix?
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    Tom Tank's Avatar
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    Re: FC Testing Q

    I have tested CYA with the 50/50 mix and it was a little under 100. For FC testing, what would the calculation be if I used 50/50 mix in the 10ml tube? Is it 1:1?

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    Mod Squad jblizzle's Avatar
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    Re: FC Testing Q

    Until you need the accuracy to know you are done (for the CC test and OCLT), you can just use 5ml of water where each drop is 1ppm.
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    Re: FC Testing Q

    Quote Originally Posted by Tom Tank View Post
    I have tested CYA with the 50/50 mix and it was a little under 100.
    If I understood that correctly, your CYA reads slightly under "100" with a 50% dilution, it means your CYA is actually ~200ppm (or more).

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    Tom Tank's Avatar
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    Re: FC Testing Q

    Sorry if I wasn't clear enough, CYA was slightly under 50 so I doubled it to 100 since I was using a 50/50 mix. Is that the correct?
    22,200 gal, IG Vinyl 3.5' - 8.5', Haywood s240 Sand Filter, Polaris 180
    manually chlorinate, 2 skimmers - 1 main drain - 3 returns plus waterfall feature
    TF-100 test kit, pool in sun ~10am - 5pm

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    Re: FC Testing Q

    Yes, that is correct.

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    pepsiholic's Avatar
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    Re: FC Testing Q

    Sorry... deleted post
    24 x 52 Round AG Outback Empire Pool 13,500 gal.
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