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Thread: Time for a SLAM?

  1. Back To Top    #1

    Join Date
    Aug 2010
    Charleston, South Carolina

    Time for a SLAM?

    I've got a plaster pool and about a month ago I noticed little black spots popping up in the deep end. Lightning had tripped the SWG breaker and so FC was down to 0. I brought it back up to 4 and took a stainless steel brush to the spots. But slowly over the course of a week or two the spots started to come back.

    The water is clear, Overnight FC loss test is just under 1.0 ppm, and the CC is .2 so how could algae be growing?
    Here are my test results?

    FC - 3
    ph - 7.9
    TA - 90
    CH - 300
    CYA - 80
    half Inground/half above ground, shotcrete pool, 19,000 gallons - KrystalKrete Krystal Blue quartz finish
    Pentair intelliflo variable speed pump - Pentair Easy Touch automation - Pentair T100 sand filter - Savi Melody LED lights - Mortex KoolDeck - Charleston, South Carolina

  2. Back To Top    #2
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Tucson, AZ

    Re: Time for a SLAM?

    If you see algae, then you need to SLAM. And while at SLAM level, you need to brush the spots to remove the protective layer to allow the chlorine to do its work.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
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  3. Back To Top    #3
    linen's Avatar
    Join Date
    Jul 2010
    Twin Cities, MN

    Re: Time for a SLAM?

    When you are doing the OCLT, is the swg off?

    Also, for 80 ppm cya, you do not want your FC below 4 ppm (ever).

    If you smear the black spots, are they green inside?

    I would follow jbliz advice and start the SLAM process and do another OCLT tonight to see what it shows at a higher FC level.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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