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Thread: Shocking the pool - 0 cc & FC loss 1 overnight water green

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    homeschoolmoxy's Avatar
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    Shocking the pool - 0 cc & FC loss 1 overnight water green

    I'm still a newbie and I'm doing pretty good with the BBB method if the weather is nice and we use the pool. A couple times in Aug and Sept we had highs of only 60 and rain for several days and the pool was neglected.
    So yesterday when I pulled the solar cover off this is what I found:
    Water clear with green stuff (algae?) settled on the bottom
    CYA ~20
    FC 1.5
    CC 0
    ph 7.8
    I vacuumed the pool and it turned a bit cloudy. Added dry acid to bring ph down to 7.3 (haven't rechecked since FC is high) Added enough bleach to get
    FC 13 at last check
    This morning
    FC 12
    CC 0
    Water still slightly greenish cloudy
    Now I assumed that if I had an algae problem I would loose more FC overnight and I should have a cc reading as well. How long should I hold the water at shock level?
    The water temp is down to 70F and we might not keep the pool open much longer.
    27 foot AG vinyl pool (17100 gallon) - Sand Dollar Filter 1.5 hp 2 speed pump
    TFTestkit

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    duraleigh's Avatar
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    Re: Shocking the pool - 0 cc & FC loss 1 overnight water gre

    How long should I hold the water at shock level?
    As per Pool School, hold it until your water is clear. Continue to brush and vacuum the junk on the bottom and run the pump 24/7.

    Why is your CYA so low? It is almost impossible to maintain adequate chlorine with CYA that low.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Mod Squad Bama Rambler's Avatar
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    Re: Shocking the pool - 0 cc & FC loss 1 overnight water gre

    Are you sure that stuff on the bottom is algae and not just dirt or sediment? I'd vacuum it all up and backwash, then run the OCLT one more time then hold it at shock level till the water clears.
    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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    homeschoolmoxy's Avatar
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    Re: Shocking the pool - 0 cc & FC loss 1 overnight water gre

    My CYA was closer to 40, but we had soooooo much rain that I had to do tons of backwashing to drain water from the pool.
    I figured for now the CYA would be okay since we don't get that much sun on the pool anyways anymore and we're closing soon.
    I'll vacuum again today and see.
    I was wondering, too if it might just be sediment since my numbers looked fine.
    27 foot AG vinyl pool (17100 gallon) - Sand Dollar Filter 1.5 hp 2 speed pump
    TFTestkit

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    frogabog's Avatar
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    Re: Shocking the pool - 0 cc & FC loss 1 overnight water gre

    Unless you have green dirt around you, or in the air... it's not just sediment. Green means algae in almost every case.

    Make sure you brush after you vacuum. It's possible that the chlorine isn't reaching enough algae to kill it properly. Mixing it up well and brushing to dig into any algae slime on the pool surface after taking as much out with the vac that you can might help or show you some combined chlorine (working active chlorine) to make you feel better about having to shock with good test results.
    Where kids swim in 54 degree water, turn blue, and giggle happily cuz they got a POOL!
    Year 3 BBB -15' x 48" Intex Metal Frame - Was using (2) 1000gph Intex cartridge filters (see Full time pumping Intex). 2012, converted to 1600gph and sand filter+SWG = Sand filter love affair!
    Don't waste time and energy looking for a better value on test kits, the TF100 is the best deal around. I did the looking and spent the extra money, but you don't have to make the same mistake. Just go here: TFTestkits. I use Pool Calculator for min/max, and shocking chlorine levels.

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