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Thread: Raising CYA with trichlor pucks question...

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    Jumpin' Joan's Avatar
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    Sep 2015
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    Raising CYA with trichlor pucks question...

    With the advent of cooler weather, hail storms and El Nino rains, my CYA has dropped from 50 to 40 and now to 30 (rounded up to the nearest 10ppm) over the last three months. During the last two months, daily chlorine loss ranges from 0 to 1ppm depending on windfall debris and airborne particulates (not to forget bird droppings) which are skimmed/vacuumed frequently. Gratefully, the 41F water continues to be sparkling and clear with minor CC levels if any.

    Today's readings:
    pH 7.5
    FC 5
    CC </= .5
    TA 70
    CH 300
    CYA 26-28 (rounded up to 30)

    Should I address the descending CYA with a leftover 3" - 8 oz. trichlor puck via the automatic feeder after the FC gets closer to 4 or maybe even 3ppm?

    I ask because PoolMath states 7 oz. of trichlor will "raise the FC by 9.6, CYA by 5.8, and lower pH .51" which concerns me because I don't want a return of metal staining due to a sudden push of chlorine/pH levels despite maintaining an appropriate HEDP sequestrant level.

    As always, thanks for your help and wishing everyone a Merry Christmas and prosperous New Year!
    Last edited by Jumpin' Joan; 12-24-2015 at 03:39 PM. Reason: Sorry... TRICHLOR not dichlor
    13 yr. old 5000 ga. inground fiberglass pool filtered by multi-port StaRite housing 300 lbs. of glass media and powered by a 1 hp single speed pump. City water supply is aquifer based, heavily laden with copper and calcium. Drought restrictions are in place. TFPC method supported by TF-100 test kit and Taylor SpeedStir.

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    Richard320's Avatar
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    Re: Raising CYA with trichlor pucks question...

    Short answer: yes.

    Remember, that pH drop will only occur after the whole puck has been dissolved, which might take a couple weeks in cold water. pH tends to rise over time, so it may just cancel things out.
    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!

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    Jumpin' Joan's Avatar
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    Re: Raising CYA with trichlor pucks question...

    Thanks Richard ~

    Just a little paranoid here when it comes to risking the dreaded return of staining. The pH does creep up predictably over a 7-10 day period with small additions of bleach to maintain water balance this time of the year so it's no big deal if trichlor moves it down a bit.

    Happy Ho Ho and all that good stuffing!
    13 yr. old 5000 ga. inground fiberglass pool filtered by multi-port StaRite housing 300 lbs. of glass media and powered by a 1 hp single speed pump. City water supply is aquifer based, heavily laden with copper and calcium. Drought restrictions are in place. TFPC method supported by TF-100 test kit and Taylor SpeedStir.

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    Casey's Avatar
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    Re: Raising CYA with trichlor pucks question...

    If you don't want the FC to go up, you can always go with stabilizer. It's just another option.
    I'd bet you my bikini you'll never get TFP water from a pool store!

    24' Sharkline Venture De Filter

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    Re: Raising CYA with trichlor pucks question...

    he's got leftover pucks.
    Outdoor (60% shaded) 22,000 gals: Mosaic tiles (concrete grout), 011018 IntelliFlo VS, Clean & Clear Cartridge Filter CCP320 filter, IntelliBrite 5g LED, Prozone PZ2-4V, Blue Devil 8way Tester, Taylor FAS-DPD Chlorine Tester K-1515A (you need this period—OTO is pretty much useless)

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