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Thread: High chlorine demand, slammed the pool 2 weeks back

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    High chlorine demand, slammed the pool 2 weeks back

    I slammed my pool 2 weeks back, chlorine levels were stable for a week, we had small rainfall 3 days back, now again I have high chlorine demand, spending too much money in chemicals . Only thing I suspect is black spots around the pool light fixtures, I don't know how to unscrew and clean those, never done that before. I backwashed my pool 2 weeks back during the slamming process, today I noticed there is a 7 psi increase.

    My Current chemistry

    FC 1.0
    CC 0.5
    ALK 70
    PH 7.8
    CYA 50

    Any recommendations?
    13K gal, IG, Gunite pool with raised spa water spill over to pool, built on 2005
    1.5 HP Hayward MaxFlo VS - June 2014
    DE Filter Model # DE6020
    Added Borates on Jun 2014

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    Mod Squad jblizzle's Avatar
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    Re: High chlorine demand, slammed the pool 2 weeks back

    Rain does not cause "chlorine demand". You let the FC get too low and that lets things start to grow. Time to SLAM again.

    Light should only require removing one screw on the top of the fixture.

    You should backwash the filter when the pressure rises 20-25% over the clean pressure, likely 7 psi is way too much.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
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    Re: High chlorine demand, slammed the pool 2 weeks back

    Quote Originally Posted by jblizzle
    Rain does not cause "chlorine demand". You let the FC get too low and that lets things start to grow. Time to SLAM again.

    Light should only require removing one screw on the top of the fixture.

    You should backwash the filter when the pressure rises 20-25% over the clean pressure, likely 7 psi is way too much.
    Thanks, Do I need to increase the Alkalinity to 90 before slamming? This time i want to slam it in a right way to avoid repeat.
    13K gal, IG, Gunite pool with raised spa water spill over to pool, built on 2005
    1.5 HP Hayward MaxFlo VS - June 2014
    DE Filter Model # DE6020
    Added Borates on Jun 2014

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    Re: High chlorine demand, slammed the pool 2 weeks back

    You do not need to adjust the TA, but you will need to adjust the pH to the low 7's before SLAMming.

    Which test kit do you have? Without a proper test kit you will not know if you have completed the SLAM and will need to continually repeat it.

    Follow the SLAM process that is linked in my signature.
    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

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    Re: High chlorine demand, slammed the pool 2 weeks back

    Quote Originally Posted by ping
    You do not need to adjust the TA, but you will need to adjust the pH to the low 7's before SLAMming.

    Which test kit do you have? Without a proper test kit you will not know if you have completed the SLAM and will need to continually repeat it.

    Follow the SLAM process that is linked in my signature.
    Ok, I have been using TF 100 since joining TF
    13K gal, IG, Gunite pool with raised spa water spill over to pool, built on 2005
    1.5 HP Hayward MaxFlo VS - June 2014
    DE Filter Model # DE6020
    Added Borates on Jun 2014

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    linen's Avatar
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    Re: High chlorine demand, slammed the pool 2 weeks back

    Quote Originally Posted by missourian
    Thanks, Do I need to increase the Alkalinity to 90 before slamming? This time i want to slam it in a right way to avoid repeat.
    Since you asked about raising TA I thought I would make sure you are using bleach/liquid chlorine to SLAM? We don't recommend trichlor or dichlor to SLAM since both of those add cya and lower ph (trichlor lowers ph more than dichlor).
    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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    Re: High chlorine demand, slammed the pool 2 weeks back

    Thanks everyone, just cleaned light fixtures, Oh my God, Nasty stuff . I just backwashed and loaded DE, according my filter specifications they recommended to charge 7.5 lbs of DE, I used attached cup, I measured 4 cup as 2 lbs. Is it correct to use?
    13K gal, IG, Gunite pool with raised spa water spill over to pool, built on 2005
    1.5 HP Hayward MaxFlo VS - June 2014
    DE Filter Model # DE6020
    Added Borates on Jun 2014

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    Re: High chlorine demand, slammed the pool 2 weeks back

    Quote Originally Posted by linen
    Quote Originally Posted by missourian
    Thanks, Do I need to increase the Alkalinity to 90 before slamming? This time i want to slam it in a right way to avoid repeat.
    Since you asked about raising TA I thought I would make sure you are using bleach/liquid chlorine to SLAM? We don't recommend trichlor or dichlor to SLAM since both of those add cya and lower ph (trichlor lowers ph more than dichlor).
    Yes I am using BBB method, no trichlor or dichlor.
    13K gal, IG, Gunite pool with raised spa water spill over to pool, built on 2005
    1.5 HP Hayward MaxFlo VS - June 2014
    DE Filter Model # DE6020
    Added Borates on Jun 2014

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    Re: High chlorine demand, slammed the pool 2 weeks back

    The only time to do a full charge of DE is when the filter is broken down and cleaned. You will only want to add around 75% of a full charge of DE. The most accurate way to know how much DE was added from your measuring cup is to weigh it if you have a scale that can measure it.
    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

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    Re: High chlorine demand, slammed the pool 2 weeks back

    Its 3rd day of my slamming process, my CC is 0.5, water is crystal clear, I loose about 1.5 ppm of FC every 4 hours, as soon as I reach 1 ppm loss for every 4 hours is it safe to call off the slamming process?
    13K gal, IG, Gunite pool with raised spa water spill over to pool, built on 2005
    1.5 HP Hayward MaxFlo VS - June 2014
    DE Filter Model # DE6020
    Added Borates on Jun 2014

  11. Back To Top    #11

    Re: High chlorine demand, slammed the pool 2 weeks back

    You'll need a drop in FC of 1 or less overnight (OCLT) along with a morning CC of 0.5 or less before the sun hits the crystal clear water. For the overnight test, see: pool-school/overnight_fc_test.

    Don't stop until then.
    Outdoor 14,000 gallon IG plaster pool built in 2000 with spillover spa, 2 hp WhisperFlo pump with MagneTek motor, Sta-Rite cartridge pool filter with 300 ft2 filtration area and 0.33 gpm/ft2 filtration rate, Aquabot Rapids 4WD robotic pool cleaner, Raypak digital gas heater, and Intermatic mechanical timer located in the Dallas-Fort Worth metroplex

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