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Thread: just want to check my numbers...

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    Aug 2007
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    just want to check my numbers...

    I've been combing through this forum on and off this summer. We bought a house last fall, which came with a pool, and everything was going "swimmingly" until about one month ago, when mustard algae hit hard, and i have been fighting a battle, initially losing, but now i think i have the upper hand, and i'm just trying to get my water back in balance.

    when the algae took over, i ended up pouring "tons" of stuff in, and shocking repeatedly......i ended up with cloudy water, which i figured was due to either high TA or high CH.....i did some diluting, i won't bore you with all my past set of numbers, but, now, thankfully, my water is back to clear, and i have the following values:

    FC = 15
    CC = 0
    pH = 7.7
    TA = 140
    CH = 220
    CYA = 80

    using the fc/cya table, it looks like i need to maintain an FC around 9 until i dilute the CYA (it was higher, and i've brought it down a bit). the FC = 15 is the result of shocking it last night, because my CC level had risen (due to all the #$%$#! i threw in there to kill the algae!). obviously, i'll be checking the FC level tomorrow, and hoping that it'll come down a bit......but, this raises two questions in my mind:

    1. what's my next step with these numbers? this is the highest the pH has been all summer, and i'm thinking i should bring that down, which would give me the opportunity to do the whole aeration thing to bring down the TA a bit...but is that my priority?[/*:m:3rvfxq02]
    2. how much higher than the fc/cya table target fc values is it safe to swim in? esp for little kids? specifically, is FC = 15 OK to swim in with the CYA = 80? [/*:m:3rvfxq02]


    thanks to all the great advice on this list - i feel much less alone in this adventure, which my husband was very dubious about, and not at all supportive of trying to manage - the only reason he didn't fill in the pool when we moved in was because it cost too much to fill it!! i'm a life-long swimmer, including lifeguard/swim instructor in high school, and swim team in college, but i've never dealt with the chemistry end!!
    Janaki
    -------
    never thought i'd own a pool, now i have one, and hope i won't let it down!

    18K gallons
    IG, vinyl
    one skimmer, one return
    1HP Jandy pump
    sand filter
    - no bells, no whistles!

  2. Back To Top    #2

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    You should continue to keep your pool at your recommended shock level until it stays at that level overnight, then you can let it come down to your recommended FC level.

    I would bring the pH and TA down. Take the pH down to 7.0, then aerate to bring it back up to about 7.2 and then bring it back down to 7.0 and then aerate again - repeat this until your TA gets down to a better range.

    You can live with the CYA at 80. If you don't want to dump more water, it will probably lower eventually, due to splash out, evap and replacing the water. You can also vacuum to waste and refill as necessary.
    Buggs

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    Quote Originally Posted by Buggsw
    repeat this until your TA gets down to a better range.
    so, what is a "better" TA range?? most of my sources seem to suggest 80-120, and 140 doesn't seem too far off that. am i better off with a value nearer 80?
    Janaki
    -------
    never thought i'd own a pool, now i have one, and hope i won't let it down!

    18K gallons
    IG, vinyl
    one skimmer, one return
    1HP Jandy pump
    sand filter
    - no bells, no whistles!

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    Re: just want to check my numbers...

    Janaki,

    Your questions are well thought out and pertinent.

    what's my next step with these numbers? this is the highest the pH has been all summer, and i'm thinking i should bring that down, which would give me the opportunity to do the whole aeration thing to bring down the TA a bit...but is that my priority?
    No. Not yet. I would make sure you have cleared your pool of all the organics by testing to see if it will hold a consistant (not much more than 1ppm drop) overnight. Once that's accomplished, you could address the pH and Alk if you like but they're not that bad...just at the high end of normal.

    OK to swim in high FC levels? IMHO, absolutely. Your high CYA reduces the effective FC so you're actually swimming in much less effective concentration than if you had no CYA. I've swum in 25ppm FC with lower CYA on more than one occassion with no affect. In fact, I've actually yet to see a post on this forum where there's been documented evidence of an outdoor pool even fading a swimsuit. In short, GO SWIMMING!
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  5. Back To Top    #5
    JasonLion's Avatar
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    I'd say you are good. Just make sure the algae is really gone as others suggested and don't worry about the TA. You could bring the PH down now or wait till it gets to 7.8 before bothering. High TA isn't a significant issue in a vinyl pool and your is only just a little high. Long term I would aim for a TA between 80 and 100 but it can be higher than that without causing any really problems (though do keep it below 200).
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  6. Back To Top    #6

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    thanks to all of you for reassuring me. it seems like the FC is holding fine at the moment, so i think i'll just sit tight, monitor daily for the next bit and see what happens.

    the early part of the summer, when the water was crystal clear, and i hadn't yet experienced the mustard algae bloom, lulled me into a sense of complacency, and now i'm feeling a bit anxious - esp about poisoning my under-6 visitors with high levels of chemicals, so the reassuring tone telling me that the CYA and FC levels are not too out of whack is really helpful.

    thanks again for the speedy response!
    Janaki
    -------
    never thought i'd own a pool, now i have one, and hope i won't let it down!

    18K gallons
    IG, vinyl
    one skimmer, one return
    1HP Jandy pump
    sand filter
    - no bells, no whistles!

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