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Thread: Overnight test - update: Passed OCLT

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    Overnight test - update: Passed OCLT

    HI-

    I have been doing the shock process for over a week, stopped for 2 days last weekend to add/replace water and started again. The pool started a bit hazy because not understanding the CYA/chlorine relationship. Also have had water mold show up when low chlorine. Has been clear for weeks. My question is that I can't seem to pass the overnight test! I came close a few days ago with only losing 1.5. I have a auto cover that goes on each night as we do not have a fence. I checked last night and closed then opened this morning and a 5 loss. It was already light outside but not directly on pool. Could that have already lowered the chlorine?

    Wondering if I need to do it before the sun comes up??

    the chlorinator has been off for weeks-once i realized what that was doing!! only adding liquid 10 or 6%. and do not see anything lurking.

    help?
    IG 24,000 vinyl lined
    18x36
    sand filter
    chlorinator
    automatic cover with no fence

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    Join Date
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    Re: Overnight test

    An overnight test should be just that, although a cover should prevent any direst loss to sunlight, Q. Is it a solar type cover that allows heating?

    If your FC use is so high you have something that is using your FC up so you should continue until passed. You could go for a higher shock level

    Stopping for 2 days will also have set you back, so your process will not have been completed. Don't give up, continue or you will stil have problems reappear
    Stuart Murray
    Scotland UK
    UK NPPOC

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    Re: Overnight test

    It was already light outside but not directly on pool. Could that have already lowered the chlorine?
    No, I don't think so. That's not enough UV exposure to make much difference.

    So, having eliminated UV as a reason for chlorine loss, the only thing left is organics (algae) in your pool. If you have a light niche, check behind that as water mold loves to hide in places like that. That said, I doubt that would account for a 5ppm loss so you simply have to replenish your chlorine daily until your overnight loss stops.

    I'd give it a couple of more days at shock value. Are you vacuuming, brushing, keeping the filter clean, etc? Doing all those things as described in Pool School will help speed the process.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Overnight test

    Hi-

    I will check behind the light-been meaning to do that!

    I have never seen any green in the pool but know that doesn't mean its not there. I feel like it must be the mold eating chlorine. Will it ever go away??? or over the winter will it come back like it did before? i opened with sheets of it, and i did end up with high amomnia. Did lots of water exchanging.

    As of now I have CYA of 65ish. I will shock a few more days and see where I get!

    I am brushing, vacuumed a few times(its clear and nothing to clean up), and filter doesnt seem to move very much but do backwash.

    Thanks-will let you know about the light
    IG 24,000 vinyl lined
    18x36
    sand filter
    chlorinator
    automatic cover with no fence

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    Re: Overnight test

    Will it ever go away??? or over the winter will it come back like it did before?
    Yes and probably not. Think of it in the simplest of terms....algae and mold (and bacteria) cannot survive in the presence of adequate chlorine. If you got them in your pool it was because the chlorine was inadequate.

    Now, I understand there are 10,000 variables to that statement above but philosophically, keep going back to that premise.....adequate chlorine keeps algae and mold away....it cannot grow. The amount you need to do this can vary somewhat from the guidelines we suggest but the idea is always the same...enough chlorine (without overdosing wildly) will keep algae and mold out of your pool.

    Once it starts to grow, it takes tons MORE chlorine to eradicate it but once you get all of it, it is fairly simple to keep it out of your pool.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Overnight test

    Dave-

    You would not believe behind the light!! wow! tons of mold-i skimmed as much out as I could and it was time to shock again. the pool was at 23.5 so upped to 25ish. I cant believe how gross it was. My husband really wiped and scrubbed the light and in the hole. we are leaving it out in water for a bit!

    WOW
    IG 24,000 vinyl lined
    18x36
    sand filter
    chlorinator
    automatic cover with no fence

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    Re: Overnight test

    Yeah, it's nasty looking (but harmless) stuff. I have gotten it behind my niches as well. A once a year removal and inspection should be something we probably should all do with lights.

    Hopefully, that will cure most of your chlorine loss. It does get in your ladders, too, so you might pull them out and let them drain for a day or two.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Overnight test

    I hope it helps with the loss as well-it has too!

    My ladder is part of the pool in the wall. I do scrub around and under it just like the regular steps into the shallow end.

    Will see what happens overnight!
    IG 24,000 vinyl lined
    18x36
    sand filter
    chlorinator
    automatic cover with no fence

  9. Back To Top    #9

    Re: Overnight test

    Well, didn't pass overnight. not totally surprised given what was in behind the light! night before it was a 7 loss (thought 5) and last night was 5 so at least better. The clarity is even better today, didn't think that was possible-it looked great before! still 1 CC

    Keeping at 25 today! hope for tomorrow!
    IG 24,000 vinyl lined
    18x36
    sand filter
    chlorinator
    automatic cover with no fence

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    Re: Overnight test

    Keep at it your numbers are going in the right direction!
    Stuart Murray
    Scotland UK
    UK NPPOC

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    Re: Overnight test

    Hi

    Well didn't make it overnight. Only 4 down though! Also the CC was barely .5.. Guess i will keep going!!

    Thanks
    IG 24,000 vinyl lined
    18x36
    sand filter
    chlorinator
    automatic cover with no fence

  12. Back To Top    #12

    Re: Overnight test

    Once again a no go on overnight! This is driving me crazy! It has been 12 days! after the first 3 days I stopped to drain water for 2 days. then back at it, but 12 days of shocking and the pool was only hazy! I guess the water mold.

    It did only lose 3 and no CC!

    so one more day??
    IG 24,000 vinyl lined
    18x36
    sand filter
    chlorinator
    automatic cover with no fence

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    Butterfly's Avatar
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    Re: Overnight test

    As of now I have CYA of 65ish.
    Since the CYA test is +/- 15ish the shock level could be a little higher.

    Tonight I suggest that you bump the FC to around 30 - 35. That is what I'd do if it was my pool
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

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    Re: Overnight test

    I also like Butterfly's idea...bump the FC just a bit.

    Poolgirl, I hear your frustration but you have no choice. You have organics in your pool and you have to kill them. Chlorine is the be3st weapon to do that with. Keep the faith, regardless of how long it takes.....there really is no common sense alternative.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Overnight test

    +1 for Butterfly's suggestion, at least you can see your FC use dropping over the last few days, which is good and suggests everything is nearly there.

    Stu
    Stuart Murray
    Scotland UK
    UK NPPOC

  16. Back To Top    #16

    Re: Overnight test

    Hi
    Thanks for all the encouragement!

    Although went from 28.5 to 26 and no CC! so close! I didn't add anymore yet and just closed the auto cover up! Didn't get to 30 like I thought

    Mouse swam by me while I was adding the last chlorine at 10:20pm! glad I saw him to get out with the net. Had one dead a bottom of pool earlier this summer!
    IG 24,000 vinyl lined
    18x36
    sand filter
    chlorinator
    automatic cover with no fence

  17. Back To Top    #17

    Re: Overnight test

    Hey

    As i know that 65 CYA is high, thinking once this shock process was over i would drop water again to try to get at least to 50! Major puck/stick user this summer!

    Do I want to do that now or just stay the course?
    IG 24,000 vinyl lined
    18x36
    sand filter
    chlorinator
    automatic cover with no fence

  18. Back To Top    #18

    Re: Overnight test

    Well I did keep shocking yesterday. Last night I tested before bed and am thinking I didn't count drops correctly. I got 30.5 after only adding to 28 1 hour earlier. Possible? Should have checked again right then! I'm wondering if I jumped by 10 drops. Anyway it 23 this morning. I must have done something wrong last might. So mad at myself! So will continue today. I took it back to 25. Had it up to 28 each shock time yesterday and once added to much on accident and think I took to 34!
    Annoyed at my own pool girl ... Me!
    IG 24,000 vinyl lined
    18x36
    sand filter
    chlorinator
    automatic cover with no fence

  19. Back To Top    #19
    stev32k's Avatar
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    Re: Overnight test

    The last time I shocked it took 24 days to clear up. If you have a ladder in the pool check the under side of the steps for algae. That's where it is hiding in my pool.
    20' x 40' IG with vinyl liner volume approx. 35,000 gal.1.5 H.P. main pump, Polaris 280 cleaner W/ 3/4 H.P. booster pump
    Hayward sand filter, 3.14 sq ft, 62 gpm. Stenner 45 MPH10 chlorine feed pump. 1 micron final filter bags (home made and very effective)

  20. Back To Top    #20

    Passed overnight test!!!!

    YEAH!

    only lost 1ppm this morning and less that .5 CC and pool has been clear for weeks! Take that Water Mold!!

    Thanks a ton to all!!!!!!
    IG 24,000 vinyl lined
    18x36
    sand filter
    chlorinator
    automatic cover with no fence

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