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Thread: When to re-test CYA if first reading is zero?

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    Join Date
    Jun 2013
    Location
    Grand Is, NY
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    2

    When to re-test CYA if first reading is zero?

    Opened pool up a few weeks ago and it was considerably black and is now cloudy blue or greenish. We have done many cartridge cleanings, added lots of chlorine, vacuumed all the crud from bottom. We had been using Pristine Blue for about 5 years and wanted to switch to this BBB method. (My husband was smelling like metal whenever he got out of pool.) I have read Pool School.
    So, I ordered the TF-100 kit and first checked for CYA which did not even register and so assuming it is at zero. Added 3 pounds of granular CYA (as directions stated on bottle) into a sock in skimmer basket which all dissolved within a few hours.
    When do I re-check the CYA level so that I can know the corresponding FC shock level?
    When should I check the alkalinity?
    When should I check the pH?

    This is all new to me...

    Can trichloroisocyanuric acid be used instead of CYA?
    Is there anytime at which we should NOT be in the pool...like after adding chlorine?

    Thanks for all your help.

    Joanikins
    12,000 gallons, oval
    AG
    cartridge
    HP 1.5
    2003
    12K gal., AG vinyl, 1.5 HP Hayward Power-Flo LX, 150 sq.ft. cartridge XStream Hayward, installed 2003, TF-100

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    Join Date
    May 2013
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    Bay City, Michigan
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    Re: When to re-test CYA if first reading is zero?

    Quote Originally Posted by joanikins
    When do I re-check the CYA level so that I can know the corresponding FC shock level?
    You basically can just assume what you aimed for is what your at. I used pool calculator and for 12,000 gallons 3lbs puts you at 30...so just assume your CYA is 30. It can take up to a week to register in the test and thats too long to wait if you have shocking to do.

    Quote Originally Posted by joanikins
    When should I check the pH?
    one time not to test ph is if your FC is greater then 10. Another time is if you just added something to adjust your PH or TA, then you need to let it filter a little while.

    Quote Originally Posted by joanikins
    When should I check the alkalinity?
    Anytime unless you've just attempted to raise or lower your PH/TA

    Quote Originally Posted by joanikins
    Is there anytime at which we should NOT be in the pool...like after adding chlorine?
    I believe as long as your not over your shock level for your specific CYA it is fine.

    As long as your FC is less than 10, go ahead and test everything except CYA, we will assume it at 30. Post your results if you need more help or questions.
    12500 gallons, 24 foot round above ground
    Hayward Sand filter, Pentair OptiFlo 1HP 2-Speed pump

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    Join Date
    May 2013
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    Re: When to re-test CYA if first reading is zero?

    Quote Originally Posted by joanikins
    Can trichloroisocyanuric acid be used instead of CYA?
    It does not appear to be for the same thing, but what do I know.

    The compound is a disinfectant, algicide and bactericide mainly for swimming pools and dyestuffs, and is also used as a bleaching agent in the textile industries.
    It reads like its more similar to bleach/chlorine than it is a stabilizer.
    12500 gallons, 24 foot round above ground
    Hayward Sand filter, Pentair OptiFlo 1HP 2-Speed pump

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    Join Date
    Jun 2013
    Location
    Grand Is, NY
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    Re: When to re-test CYA if first reading is zero?

    Thanks Scott for your expedient reply. That helps us out and we are very excited about having sparkling water.
    12K gal., AG vinyl, 1.5 HP Hayward Power-Flo LX, 150 sq.ft. cartridge XStream Hayward, installed 2003, TF-100

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    Richard320's Avatar
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    Location
    San Dimas, CA (LA County)
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    18,768

    Re: When to re-test CYA if first reading is zero?

    Quote Originally Posted by joanikins
    Opened pool up a few weeks ago and it was considerably black and is now cloudy blue or greenish. We have done many cartridge cleanings, added lots of chlorine, vacuumed all the crud from bottom. We had been using Pristine Blue for about 5 years and wanted to switch to this BBB method. (My husband was smelling like metal whenever he got out of pool.) I have read Pool School.
    So, I ordered the TF-100 kit and first checked for CYA which did not even register and so assuming it is at zero. Added 3 pounds of granular CYA (as directions stated on bottle) into a sock in skimmer basket which all dissolved within a few hours.
    When do I re-check the CYA level so that I can know the corresponding FC shock level?
    When should I check the alkalinity?
    When should I check the pH?

    This is all new to me...

    Can trichloroisocyanuric acid be used instead of CYA?
    Is there anytime at which we should NOT be in the pool...like after adding chlorine?

    Thanks for all your help.

    Joanikins
    12,000 gallons, oval
    AG
    cartridge
    HP 1.5
    2003
    Trichlor contains CYA, but it will take far too long for it to dissolve to get any meaningful CYA in the pool for weeks.

    Also note, Trichlor raises FC, raises CYA, lowers pH, and as a result of that, lowers TA. You'll be juggling four parameters at once, and - no insult intended, here - you're not to that level of expertise yet.

    Granular stabilizer takes about a week to show up reliably on the test. You can measure everything else whenever you please, but allow half an hour after adding anything before checking it. Longer would be better. Brushing also helps set up cross-currents which helps mix chemicals.

    For calculating the shock level, just use your calculated CYA level. It's in there, it just doesn;t show up on the test right away. It appears you were shooting for 30 CYA, so use that to establish the FC shock level.

    And you haven't asked, but TA is the very last thing you worry about. Unless by some freak of nature it's less than 50, deal with it after the pool is clear.
    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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