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Thread: Tested after shocking pool, some advice appreciated

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    Tested after shocking pool, some advice appreciated

    Hi all,

    Great forum and I just got the test kit today.

    My pool (inground 15x30 approx 15000 gallons) was a green pond and was able to shock it with tons of liqued chlorine and now it is clear. I decided to run the tests are here are the results:

    FC-22 (cause I shocked it recently)
    CC 0
    TC 22
    PH 8
    TA 110
    CH 210
    CYA 100

    Questions I have are:

    1) I admit, I have used tricholor pucks in the skimmer to maintain chlorine levels and that is probably why my CYA is high. Should I drain some of the pool to get the CYA down or is 100 OK? If I do need to drain, how much should I drain? I dont plan on using pucks in the future and will shock with bleach instead of the liqued chlorine.

    2) On the PH issue, should I wait to fix that once the chlorine levels do down the normal range? From the chart it looks like my FC should be 7-11 for 100 CYA pool?

    Thanks for any advice

    -Steve

  2. Back To Top    #2

    Join Date
    Jul 2007
    Location
    Florida
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    Welcome pH will incorrectly read higher than actual when FC is higher than about 15. So don't trust that value yet.

    Unfortunately doing a partial drain is the only way to get rid of excess CYA. Did the black dot disappear right AT 100, or way before that? Due to test limitations, there's really no accurate way of knowing what the true CYA value is when you read past 100... could be 120, 150, 200, etc. Normally you want CYA levels around 50.
    22,000 gal in-ground, 3-8ft
    Cartridge filter
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    duraleigh's Avatar
    Join Date
    Apr 2007
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    Sebring, Florida
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    Basco,

    Welcome to the forum!! Rimshaker's advice is right on the money. Wait 'till your FC drifts down below 10ppm and then your pH test should be pretty accurate. Adjust if necessary.

    Your life will be easier if you'll drain out some water and get that CYA down around 40-60ppm. 100 is manageable but barely so and it'll simply make EVERYTHING you do to your pool simpler if your CYA is lower. If water's pretty cheap in your area, a 50% drain will bring your CYA right where it needs to be.

    You may have made a typo but Clorox and liquid chlorine are interchangeable and you can use one or the other....only the per cent chlorine is different.

    You've got a good grasp on your chemistry and sounds like you're ready to have a nice sparkling pool this summer. Nice work on clearing that algae bloom.....that gives a lot of folks fits.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  4. Back To Top    #4
    Rimshaker and Duraleigh,

    Thanks for the replies. I think I will plan to do a 50% drain on the pool. The measurement for 100 was right at the 100 mark on the tube, not past it.

    Also, the chlorine ive been using to shock is the 10% sodium hypochlorite bought at home depot.

    Thanks again!

  5. Back To Top    #5
    Guest

    Re: Tested after shocking pool, some advice appreciated

    Quote Originally Posted by Basco
    Hi all,

    Great forum and I just got the test kit today.

    My pool (inground 15x30 approx 15000 gallons) was a green pond and was able to shock it with tons of liqued chlorine and now it is clear. I decided to run the tests are here are the results:

    FC-22 (cause I shocked it recently)
    CC 0
    TC 22
    PH 8
    TA 110
    CH 210
    CYA 100

    Questions I have are:

    1) I admit, I have used tricholor pucks in the skimmer to maintain chlorine levels and that is probably why my CYA is high. Should I drain some of the pool to get the CYA down or is 100 OK? If I do need to drain, how much should I drain? I dont plan on using pucks in the future and will shock with bleach instead of the liqued chlorine.
    Bleach and liquid chlorine are the same thing...use whichever is more cost effective. the only difference is the strength. Bleach is usually 5.25% or 6% while liquid chlorine is usually 6%, 10% or 12.5%

    DO NOT, I REPEAT DO NOT PUT PUCKS IN YOUR SKIMMER UNLESS YOU WANT TO RUN THE RISK OF RUINING YOUR PUMP SEAL AND, IF YOU HAVE A CARTRIDGE FILTER, YOUR FILTER CARTRIDGE!

    2) On the PH issue, should I wait to fix that once the chlorine levels do down the normal range? From the chart it looks like my FC should be 7-11 for 100 CYA pool?

    Thanks for any advice

    -Steve
    How much to drain is hard to say sometimes since CYA can deposit on the pool surface and in the plumbing and as the level drops it can redissolve. Also, there is some evidence that CYA above 100 ppm can damage plaster.

  6. Back To Top    #6
    DO NOT, I REPEAT DO NOT PUT PUCKS IN YOUR SKIMMER UNLESS YOU WANT TO RUN THE RISK OF RUINING YOUR PUMP SEAL AND, IF YOU HAVE A CARTRIDGE FILTER, YOUR FILTER CARTRIDGE!
    Yeah I was following the advice of the pool contractor when he was showing me how to run the pool, hope I didnt do too much damage being ive been using pucks for a few years now

    So is it recommended to just apply bleach to maintain chlorine levels rather than using pucks or any stabilizer?

  7. Back To Top    #7
    JasonLion's Avatar
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    Silver Spring, MD
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    37,879
    You need stabilizer (CYA), but the CYA level needs to be managed independently from the chlorine level. The pucks do both at once so if you aren't careful the CYA level quickly gets way too high. If you are using pucks, and there are times to do that, they are best used in a puck feeder that is specifically designed for them. I believe Waterbear's point was specifically to avoid putting them in the skimmer, which can cause equipment damage over time.
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