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Thread: Overnight Loss Holding at 2.5 while SLAMing

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    Join Date
    Jun 2016
    Location
    Graysonville, MD
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    5

    Overnight Loss Holding at 2.5 while SLAMing

    Hello Everyone,

    I opened our pool this spring to find the CYA at ZERO. We had a warm and rainy winter here in Maryland, and this is was the first winter with a mesh Loop-Loc cover. I added stabilizer to the pool to bring to 35 ppm, however, the pool would not hold chlorine. Based on information found here on the threads, I thought that I most likely have an ammonia problem, but the ammonia test strips come up negative. The pool is crystal clear, so possibly an algae bloom that I can't see, or some type of bacteria. Whatever it is, I started the SLAM process 10 days ago. Here are the numbers prior to SLAMing (I use a Taylor FAS-DPD kit).

    FC 0.2
    CC 1.0
    PH 7.4
    TA 90
    Hardness: 210
    CYA: 35

    At day 10, the pool is still crystal clear, and CC is at Zero. I have been maintaining a shock level of 14ppm. My initial overnight loss was 8.0 ppm, but it trended down to 2.5 and have been stuck there for the last 3 days. I am not being impatient, I simply don't want to continue at shock level if you guys feel I am ready to stop. I am asking based on the following reasons:

    1.) I have read in the threads that some stop the SLAM when the loss is between 2-3ppm (because of inconsistent testing).
    2.) The pool is surrounded by trees, we continue to get a lot of rain, and I also find frogs, mice, an debris in the skimmer basket almost every morning.

    If the consensus here is to keep shocking, then I'll keep going. Also, if by the info I have provided (or left out) makes you feel I am doing something wrong, please let me know!

    Thank you
    13,000 Gallon, In-ground, concrete, DE Filter, Mid-Atlantic

  2. Back To Top    #2
    Texas Splash's Avatar
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    Jun 2014
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    South-Central Texas, Marion/San Antonio
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    Re: Overnight Loss Holding at 2.5 while SLAMing

    Hi Rych and welcome to TFP! Don't stop. Any FC loss past 1 ppm during the OCLT is a fail. So something is eating your chlorine (FC) and you need to find it. But I would increase your SLAM FC level to 16 as I would round-up your CYA to 40 for SLAM purposes. All the debris in your pool may be a nuisance, but I doubt that's directly effecting the SLAM. But definitely make sure you use a skimmer sock to catch that stuff.

    How has everything else been going for the SLAM (link below)? Filter pressure increase much (past 25%), sweeping, brushing consistently? Anything in your pool that could harbor algae (i.e. pool light (behind in the niche), wedding cake steps, ladder, etc)? Now's the time to get exceptionally picky about anything in that water.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  3. Back To Top    #3

    Join Date
    Jun 2016
    Location
    Graysonville, MD
    Posts
    5

    Re: Overnight Loss Holding at 2.5 while SLAMing

    Thanks for the reply,

    OK, I will round up to 16, but it has typically been in the 18-20 range-as I have kept a cushion for loss. I have been adding chlorine when it gets to 15, so I will change that to 17.

    I have scrubbed the ladder, but I have not removed the light; I will do that tomorrow.

    Filter pressure is fine, I have not had to back flush during the SLAM. I sweep with the dolphin robot at least every other day and clean the filters after each use.

    Quote Originally Posted by Texas Splash View Post
    Hi Rych and welcome to TFP! Don't stop. Any FC loss past 1 ppm during the OCLT is a fail. So something is eating your chlorine (FC) and you need to find it. But I would increase your SLAM FC level to 16 as I would round-up your CYA to 40 for SLAM purposes. All the debris in your pool may be a nuisance, but I doubt that's directly effecting the SLAM. But definitely make sure you use a skimmer sock to catch that stuff.

    How has everything else been going for the SLAM (link below)? Filter pressure increase much (past 25%), sweeping, brushing consistently? Anything in your pool that could harbor algae (i.e. pool light (behind in the niche), wedding cake steps, ladder, etc)? Now's the time to get exceptionally picky about anything in that water.
    13,000 Gallon, In-ground, concrete, DE Filter, Mid-Atlantic

  4. Back To Top    #4
    Texas Splash's Avatar
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    Jun 2014
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    Re: Overnight Loss Holding at 2.5 while SLAMing

    Definitely the light! Also, see if your ladder steps come apart. Those have been little treasure-troves for algae.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

  5. Back To Top    #5

    Join Date
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    Graysonville, MD
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    Re: Overnight Loss Holding at 2.5 while SLAMing

    Texas Splash,

    Thank you so much for the great advise. I pulled out the light and found green algae behind the bezel. I also pulled the ladder out and found some in, on, and around the bumpers that I didn't see before. After eliminating that algae, my FC level dropped only 0.5 overnight. My water is crystal clear, and I have no CC. As soon as this FC drops (the bright sun today should do that quickly) we will be taking a dip!!

    So, for all of you struggling with the SLAM, hang in there, be patient, and follow the advise from the moderators! It took 12 days for my SLAM, and I was close to stopping early, but persistence paid off.

    Thanks again,

    RP
    13,000 Gallon, In-ground, concrete, DE Filter, Mid-Atlantic

  6. Back To Top    #6
    Texas Splash's Avatar
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    Re: Overnight Loss Holding at 2.5 while SLAMing

    Outstanding! That's great news. Glad to hear you found those sneaky hiding places. Have a great weekend!
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

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