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Thread: Question about test results - CC seems too high

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    Question about test results - CC seems too high

    I have read up on Pool School and ordered the TF-100 test kit to make more accurate tests. It is clear that I need to shock the pool. We have some algae, but the pool is still pretty clear. The results from my testing (2 of them) show the Combined Chlorine very high (7.5ppm). Granted, my experience with this stuff is close to nil. Thus, my post here.

    Do these combined chlorine levels seem so far out of whack that I mucked up the test??? Or, are these results high, but reasonable. Here are the specifics

    pH - 7.6
    FC - 4ppm
    CC - 7.5
    CYA - 50
    TA - 105

    SWG pool, ~16,000 gallons. Also, it should be noted that I dumped 1 gallon of regular 6% chlorine bleach in the pool the night before to try and slow the rate of growth until the test kit arrived in the mail. Perhaps this is relevant.

    Any help would be appreciated.

    Todd
    ~18.5K gallon plaster - two level / spa to pool waterfall
    Pentair WhisperFlo WFE-28 Pump, Pentair Clean and Clear Filter
    Hayward Pool Vac Ultra Cleaner

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    JasonLion's Avatar
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    Re: Question about test results - CC seems too high

    Welcome to TFP!

    A CC reading of 7.5 is a bit higher than I would expect, but still plausible.

    With both visible algae, and a high CC level, you definitely need to shock the pool.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Question about test results - CC seems too high

    Thanks Jason,

    I read up a bit more on testing (via this site). Learning more by the min. After reading some more, it appeared I may have been adding drops in the chlorine test a bit too slowly. There is a post on the site that recommends ~1 sec per drop.

    After doing the test a bit faster the results dropped.

    FC - 3.6
    CC - 5.5

    I test this twice with the same result. So, I moved on and am currently in the process of "nuking" the pool.

    Wanted to post this update in case it can help others that are new to these detailed tests.

    Thanks again.
    Todd
    ~18.5K gallon plaster - two level / spa to pool waterfall
    Pentair WhisperFlo WFE-28 Pump, Pentair Clean and Clear Filter
    Hayward Pool Vac Ultra Cleaner

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    Re: Question about test results - CC seems too high

    Okay I am back with another question. I have brought the pool up to the recommended shock level of 25 ppm. But the CC went from 5.5 to 16.5 ppm!!

    I just can't wrap my head around the fact that the CC number is correct. I have read the instructions 100 time. I am doing the test correctly...according to said directions. Can the introduction of all that FC cause the CC to jump that high??

    Thanks in advance.
    Todd
    ~18.5K gallon plaster - two level / spa to pool waterfall
    Pentair WhisperFlo WFE-28 Pump, Pentair Clean and Clear Filter
    Hayward Pool Vac Ultra Cleaner

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    JasonLion's Avatar
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    Re: Question about test results - CC seems too high

    It sounds like you have ammonia in the water. Ammonia is very efficient at turning chlorine into CC. This sometimes happens over the winter when CYA breaks down into ammonia (along with some other things that aren't important). Did your CYA level go down over the winter?

    Regardless of how it happened, the solution is the same: add more chlorine. Eventually the chlorine will catchup with all of the ammonia and start breaking down the CC and after that things will get back to normal.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Question about test results - CC seems too high

    Yes, my CYA did drop over the winter to the tune of around 40 (Oct to Mar). Of course, the PS told me not to worry about it. So much for listening to the advise of 16 year old students working at the PS! Can't tell you how glad I am that I'm now testing my own water and using this site.

    Okay, so the plan is the same. Keep pumping in FC to keep the target level. CC will go down eventually.

    Thanks again Jason

    Todd
    ~18.5K gallon plaster - two level / spa to pool waterfall
    Pentair WhisperFlo WFE-28 Pump, Pentair Clean and Clear Filter
    Hayward Pool Vac Ultra Cleaner

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    Re: Question about test results - CC seems too high

    Nothing to add but to welcome you to the forum and reaffirm that you have got a good plan....keep the FC going into the pool!
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Question about test results - CC seems too high

    Hi tlhwxman and welcome to TFP!
    I see your learning just fine grasshopper
    Just keep reading here and this science that is taught here will make perfect sense when your pool does exactly what it's told to do!
    You will soon suffer from Poolsparklyitis!

    Chuck
    Swim n Play 21' round, expandable 72" liner, 6FT deep center, buried 14", 12,750 Gallons
    Waterway 1HP-2 speed with 22" Sand filter
    TF-100 test kit
    Thanks to TFP my pool is perfect all the time :party:
    I now suffer from Sparklypoolitis! :whoot:
    I am a Platinum contributor because I want everyone who comes here to Trouble Free Pool to have the same success that I enjoy with my pool and family.

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    Re: Question about test results - CC seems too high

    Thanks everyone for the warm welcome.

    As stated earlier, I will continue to post my result on the thread to help others in the future. I don't have a specific question on this one

    This mornings results (one night of shock).

    FC 21 (loss of 4ppm)
    CC 10.5 (drop of 6ppm)

    As Charlie Sheen would say; "Winning!"
    ~18.5K gallon plaster - two level / spa to pool waterfall
    Pentair WhisperFlo WFE-28 Pump, Pentair Clean and Clear Filter
    Hayward Pool Vac Ultra Cleaner

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    maxepr1's Avatar
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    Re: Question about test results - CC seems too high

    You've got the 'TIGER BLOOD" now! lol
    40'x19' IG Diamond Brite 29K 4' Waterfall/Dive Rock FNS60 DE Inteliflo VS 2hp Whisperflo pumps Aqualogic(P4) SWG TF100 Tester


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  11. Back To Top    #11

    Re: Question about test results - CC seems too high

    Okay, I have a couple of follow up questions and an update. This mornings readings were FC-24.5 and CC-1.0. So things are moving along. First question

    1) Once the pool is free of CC and FC does not decrease overnight, do I simply just let FC drop until back to target levels? Is there anything else to look out for when returning to normal levels? This part wasn't that clear in the shock procedures.

    Okay second item - We have a vinyl pool with plastic stairs. We have had a recurring problem with staining and have been using ascorbic acid to clean it up. Since we started the shock process the staining seems to be getting slightly worse. Did some searching on here and it seems that high Chlorine and high pH will facilitate more staining as metals are precipitated out. I always thought the staining was algae of some sort, but now not so sure.

    2) Could the high chlorine from the shock and increased staining lend evidence to the fact this is iron staining?
    3) Should I start the Ascorbic Treatment right after the shock is done (after FC comes down obviously)? Any reasons why this would be a bad idea?

    Thanks
    Todd
    ~18.5K gallon plaster - two level / spa to pool waterfall
    Pentair WhisperFlo WFE-28 Pump, Pentair Clean and Clear Filter
    Hayward Pool Vac Ultra Cleaner

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    Re: Question about test results - CC seems too high

    Yeah, once your water is crystal clear and you meet the FC and CC criteria, simply let the FC drift back to normal levels per the FC/CYA chart.

    the answer to 2) is "yes"

    I would try it another way before doing the somewhat costly and time consuming ascorbic acid treatment. Try lowering your ph down to around 7.0 - 7.2 with muriatic and holding it there for perhaps as long as a week. See if the low pH doesn't help put the iron back in suspension. If it works, keeping your pH down that low permanently may keep it from reappearing.

    If it doesn't work, then you can do the AA treatment with nothing much lost.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Question about test results - CC seems too high

    Okay, thanks Dave. I will try that. However, won't keeping the pH that low permanently have other repercussions? Would it also be an eye irritant at that point as well? Just curious. Although, it does seem like a cheaper method than feeding in Ascorbic acid all the time! That appeals to me.

    Todd
    ~18.5K gallon plaster - two level / spa to pool waterfall
    Pentair WhisperFlo WFE-28 Pump, Pentair Clean and Clear Filter
    Hayward Pool Vac Ultra Cleaner

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    JasonLion's Avatar
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    Re: Question about test results - CC seems too high

    If this goes on long enough that swimming with low PH becomes a problem, you can just keep the PH at 7.2 to 7.4 instead of keeping it below 7.2. You definitely want the PH low during an ascorbic acid treatment, but long term 7.2 is a good minimum.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  15. Back To Top    #15

    Re: Question about test results - CC seems too high

    Okay - its been almost 10 days. Thought I would close this thread with the results.

    Shock treatment finished up as one would expect. It took nearly a week to eat up all the CC. As stated above, the iron staining was a huge problem and ramped up during the shock. It was hard to look at the wife was not pleased. I told her to wait it out. After the shock, I brought the pH down to 6.8 and put in ascorbic acid.

    The Results? -> Presto-chango crystal clear pool!

    FC 4.0
    CC 0.0
    pH 6.8 (will fix this)
    CYA 75
    TA 80
    CH 210
    Salt 3400

    My next task is to become a TFP Lifetime Supporter, then get my swimsuit on and go swimming.

    Thanks for the help folks!

    Todd
    ~18.5K gallon plaster - two level / spa to pool waterfall
    Pentair WhisperFlo WFE-28 Pump, Pentair Clean and Clear Filter
    Hayward Pool Vac Ultra Cleaner

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    maxepr1's Avatar
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    Re: Question about test results - CC seems too high

    Enjoy!
    40'x19' IG Diamond Brite 29K 4' Waterfall/Dive Rock FNS60 DE Inteliflo VS 2hp Whisperflo pumps Aqualogic(P4) SWG TF100 Tester


    Pool School, Pool Calculator,TFTestKits,

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    Re: Question about test results - CC seems too high

    Congratulations on a shock-job well done

    Jason, TFP Moderator
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