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Thread: My no good, awful, very bad SLAM

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    My no good, awful, very bad SLAM

    Hello,

    After using TFP effectively all last summer, I have had a rough start to the year. I tried to SLAM my pool twice only to have a PVC pipe burst preventing me from running the filter effectively ending my SLAM.

    This weekend I am giving it a third try. I have a 44k gallon, inground, plaster pool with a SWG.

    The only things I have put in the pool are: water, salt, bleach - in 16 gallon doses (albeit some lavender scented and some low splash which I just realized is a mistake) and muriatic acid.

    While last time I SLAM'd, the pool maintained high chlorine levels; this time when I dump 16 gallons of bleach in the pool and it FC and CC drop to 0.5 and 1.0 in half a day.

    I woke up to FC 0.5, CC 1.0, CYA 45. This am I dumped another 16 gallons of bleach (regular this time!) into the pool, waited one hour and my readings are:

    FC 22.0
    CC 0.0
    PH 8.0
    TA 75
    CH 125
    CYA 50

    A few questions:

    1) I appear to have had a leaking DE filter which has made the pool look milky/dusty/opaque, this happened last year and took a long time to correct. How should I think about ending the SLAM if the water isn't clear?

    2) I have a lot of white foam on top of the pool (likely from my boneheaded use of splash proof bleach). Is there a way to get rid of this? Is it hazardous?







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    Shekkie's Avatar
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    Re: My no good, awful, very bad SLAM

    I think that foam will dissipate eventually but you can skim it off with a bucket/large dustpan to speed up the process a bit.

    Are you sure that pool is 44K gallons? From the pic I'd guess low-ish 20's.
    33k(ish) gallon, IG, vinyl liner, Pentair IC60 SWG, Pentair Triton II sand filter, 1.5hp Pentair VS pump (SuperFlo), Sta-Rite (Pentair) 400K BTU heater (LP), (2) Pentair LED spa lights, TF-100 test kit w/speed stir

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    TFP Guide


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    Re: My no good, awful, very bad SLAM

    Hi, welcome to TFP!

    You are done with your SLAM when:
    • CC is 0.5 or lower;
    • You pass an OCLT (ie overnight FC loss test shows a loss of 1.0 ppm or less);
    • And the water is clear.

    When all three are true, you are done SLAMing and can allow the FC to drift down to normal levels.

    The foam is probably from the splash-less and/or scented bleach. Give it time, it will dissipate.

    Please add your pool info to your signature - see here: Pool School - Read This BEFORE You Post
    Gene
    ​12,300 gal IG play pool - Pebbletec - built 10/1999 || Hayward S360SX 36" sand filter || Hayward Ecostar SP3400 VSP || A&A In-Floor cleaning system || Quik Water Leveler || Quik Dek-clor (limited use)
    TF-100 testkit / Speedstir - A good test kit is not an expense, it's an investment

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    duraleigh's Avatar
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    Re: My no good, awful, very bad SLAM

    in 16 gallon doses
    That is incorrect. You put in enough bleach to get back to SLAM level, which depends on Your CYA Your CYA of 50 requires an FC value of 20 ppm. You must first measure your FC and then add enough to get back to 20 ppm FC. You do not add 16 gallons at a time.

    To finish the SLAM,
    1. Your pool water is sparkling and there is no visible algae (dead or alive)
    2. Your CC's are .5ppm or less
    3. You can hold your FC overnight without losing more than 1ppm.

    So, you cannot finish the SLAM with murky water.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  5. Back To Top    #5

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    Re: My no good, awful, very bad SLAM

    16 gallon doses is what the calculator says I need to go from 1.0 to SLAM levels. Because my filter kept breaking I kept getting back to FC of 1.0 or less. Once I get FC level that are higher I will add less bleach.

    My CC's are coming back 0.0 or 0.5.

    My pool is murky (I think) because I am shooting DE out of a filter.

    I have had this problem before and it took a while to fix. Should I SLAM until there is no DE in the pool or should I stop b/c my CC levels are 0.0?



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    Re: My no good, awful, very bad SLAM

    Also, thank you for your help and counsel duraleigh, proavia and shekkie.

    I will add a signature when I get to a PC for some reason I can't set up a signature in the app or from my iPhone.

    Thanks again



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    Re: My no good, awful, very bad SLAM

    Quote Originally Posted by M10507 View Post
    16 gallon doses is what the calculator says I need to go from 1.0 to SLAM levels. Because my filter kept breaking I kept getting back to FC of 1.0 or less. Once I get FC level that are higher I will add less bleach.

    My CC's are coming back 0.0 or 0.5.

    My pool is murky (I think) because I am shooting DE out of a filter.

    I have had this problem before and it took a while to fix. Should I SLAM until there is no DE in the pool or should I stop b/c my CC levels are 0.0?


    Sent from my iPhone using Tapatalk
    Can you tell us how you are testing your water? And....how often are you testing then dosing with chlorine?

    The idea behind SLAM is to keep your FC at shock level for your CYA until you pass three criteria

    Clear water
    OCLT of 1 or less
    CC of less than .5

    The DE sounds like another issue have you identified a problem with your filter?
    18*36*23 true "L" vinyl IG 29,000 gallons. SWG. TF-100 test kit.
    http://tftestkits.net/splash-page.html

  8. Back To Top    #8

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    Re: My no good, awful, very bad SLAM

    Quote Originally Posted by AimeeH View Post
    Can you tell us how you are testing your water? And....how often are you testing then dosing with chlorine?

    The idea behind SLAM is to keep your FC at shock level for your CYA until you pass three criteria

    Clear water
    OCLT of 1 or less
    CC of less than .5

    The DE sounds like another issue have you identified a problem with your filter?
    I was testing every few hours (with a Taylor test kit) then bursting pipes stopped the SLAM (and with it the testing) I have been testing twice a day over the last few days then every hour today.

    I keep getting CC levels of 0.

    I have ordered replacement grids for my filter. They should arrive tomorrow and I will change that.

    If I set an alarm for 5:30 tomorrow AM and confirm a OCLT of 1.0 would you stop SLAMming despite the DE or would you keep going?



  9. Back To Top    #9
    Mod Squad zea3's Avatar
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    Re: My no good, awful, very bad SLAM

    Once your filter is repaired you should be able to filter out whatever DE is in suspension and vacuum up what has dropped onto the floor. Keep going with the slam, the DE won't be an issue after the new grids are in. OCLT is the last step in determining if the slam is completed. You won't be able to tell if you have clear water until the DE is cleaned up.
    TFP Moderator
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  10. Back To Top    #10

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    Re: My no good, awful, very bad SLAM

    Thanks Zea3. I will put the new grids in today and see what happens. In theory the pool should run through the filter in 7-8 hours. We will see.

    I did the OCLT test last night and passed.

    Sadly another PVC pipe burst. Ugh.



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