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Thread: Passed OCULT once, next time - nope!

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    Join Date
    May 2015
    Paxinos PA

    Passed OCULT once, next time - nope!

    Two nights ago, we did an OCULT and passed. Whew! I thought we had turned around. Last night we did a re-trial just to make sure. Nope. We lost 1.2ppm FC and CC is at 1. Is this normal?

    I did a re-trial because I wanted to make sure we were in the clear before putting the solar cover back on at night time. I need to rule out that there isn't something on the cover causing us to lose significant amounts of chlorine over night.
    22,000 gal 16x34, IG, vinyl (7/14)
    DE Hayward Perflex extended cycle
    Hayward Super Pump
    Aquacal heat pump
    TF-100 test kit

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    Mod Squad Texas Splash's Avatar
    Join Date
    Jun 2014
    South-Central Texas, Marion/San Antonio

    Re: Passed OCULT once, next time - nope!

    You did the right thing! Your gut told you something wasn't right, and it's good you double-checked. Having said that, let's review the SLAM requirements:
    The following 3 objectives must be met:
    1. Water is clear
    2. You do not lose any more than 1ppm of FC overnight (that's the OCLT)
    3. CC (Combined Chlorine) is <.5
    ** You MUST meet ALL 3 items above to properly do a SLAM. Simply “spiking" the FC higher than normal isn't SLAMming, therefore there’s a good chance your algae will return.

    Now if you have a concern about the cover somehow contributing the your OCLT, I supposed you could just leave it off for a night and do an OCLT the next morning. If it passes, put the cover on and try again the next morning to compare. Otherwise, it may simply be that you still have a small amount of residual matter in the water that is trying to fight the bleach. Stay with it!
    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
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    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    SouthWest Alabama

    Re: Passed OCULT once, next time - nope!

    I always suggest that people run the OCLT two nights in a row just to make sure that the first one wasn't a fluke. It's not part of the process, and most of the time one night is enough, but there are a few times where someone will pass the OCLT and not be completely done SLAMing.

    I'd bring it back to slam level for a couple of days and then run it again. You can also put the solar cover on it one day during slam to kill anything that may be on it.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Join Date
    Jun 2011
    Long Beach, CA

    Re: Passed OCULT once, next time - nope!

    removed post
    16k gal plaster with raised spa, Jandy DEV60 filter, 2 HP 2-speed SHPF Jandy Stealth pump
    Hayward Aqua Rite T-15 SWCG, Jandy LXi 400k BTU NG heater, 350 sq.ft. of Sun Star solar panels, TF-100 Test Kit, Dolphin s300i Cleaner
    Test Kits . Pool Math . Chlorine/CYA Chart . The SLAM Process

  5. Back To Top    #5
    Isaac-1's Avatar
    Join Date
    May 2010
    SW Louisiana

    Re: Passed OCULT once, next time - nope!

    Double check for places with poor circulation where algae may be hiding, under steps, behind light niches, etc.
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
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