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Thread: Do I add shock when it is at shock level?

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    Do I add shock when it is at shock level?

    So do I add shock in the morning when it is still at shock level but the CC is at 2? The pool is sea green cloudy and I don't see a visible change each day. I am brushing every day and vacuumed this morning. I want this process to go faster but it just doesn't when it gets to be a frog pond in the winter since we have no cover. Have added DE twice a day the past 3 days as well but don't know that I see that accelerating the process. Put in a new filter gauge so wonder about how often to backwash since there is disparity it seems on that question on this site.

    Thanks for any input.


    FC 16
    CC 2
    pH 7.2
    CYA 40
    18,000 gallon IG vinyl
    Hayward S220T sand filter, replaced sand 2013
    Sta-Rite pump, 1HP?
    New liner, 5/12; pool built in 1981;

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    Richard320's Avatar
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    Re: Do I add shock when it is at shock level?

    No, you don't need to add any more shock.

    By "shock," I hope you mean liquid pool chlorine or bleach, because all the "shock" products in powder forms carry side effects. You may be adding more CYA each time, which would mean 16 FC isn't high enough anymore. If it's non-chlorine shock, it messes with the CC test and you may never reach the point where CC goes down.

    The way it goes is: test FC, plug the result into poolmath as now and target 16. Then add whatever it says to get to 16. You're at 16 and you want 16 so you need nothing.

    CC will rise and fall during the SLAM process. Sunlight will burn some off, so it's not surprising that it's higher in the morning.

    DE won't accelerate the chemical processes, it only improves the filtration. If the water is still greenish after a couple days, something is going wrong. Algae is still growing. The chlorine level hasn't been maintained high enough or there's still too much debris down in the bottom. Almost everyone reports the pool is grey within three days.

    And I've never seen any inconsistency here about when to backwash. The recommendation has always when when the baseline clean pressure rises 25% or you see noticeably reduced flow.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Do I add shock when it is at shock level?

    Quote Originally Posted by Richard320 View Post
    No, you don't need to add any more shock.

    By "shock," I hope you mean liquid pool chlorine or bleach, because all the "shock" products in powder forms carry side effects. You may be adding more CYA each time, which would mean 16 FC isn't high enough anymore. If it's non-chlorine shock, it messes with the CC test and you may never reach the point where CC goes down.

    The way it goes is: test FC, plug the result into poolmath as now and target 16. Then add whatever it says to get to 16. You're at 16 and you want 16 so you need nothing.

    CC will rise and fall during the SLAM process. Sunlight will burn some off, so it's not surprising that it's higher in the morning.

    DE won't accelerate the chemical processes, it only improves the filtration. If the water is still greenish after a couple days, something is going wrong. Algae is still growing. The chlorine level hasn't been maintained high enough or there's still too much debris down in the bottom. Almost everyone reports the pool is grey within three days.

    And I've never seen any inconsistency here about when to backwash. The recommendation has always when when the baseline clean pressure rises 25% or you see noticeably reduced flow.
    Thanks, yes I am using 12% liquid shock.

    Good to know that CC will fluctuate. Do I even need to test for CC if my water is not clear?

    I was hoping the DE would speed up the filtering process and clear it quicker. The water has lightened from dark green to sea green and sometimes looks bluish. And I can now see the second step on the pool ladder.

    So now I am wondering if I need to be backwashing more often. Using DE definitely makes the pressure rise. How long can I let it be a bit higher after adding DE? Am I getting benefit of better filtration if it is at the higher pressure?
    18,000 gallon IG vinyl
    Hayward S220T sand filter, replaced sand 2013
    Sta-Rite pump, 1HP?
    New liner, 5/12; pool built in 1981;

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    Re: Do I add shock when it is at shock level?

    The answers you need are all in the SLAM article in Pool School. That should be your bible until the SLAM is complete
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    PAGirl's Avatar
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    Re: Do I add shock when it is at shock level?

    Quote Originally Posted by mamalou23 View Post
    Thanks, yes I am using 12% liquid shock.

    Good to know that CC will fluctuate. Do I even need to test for CC if my water is not clear?

    I was hoping the DE would speed up the filtering process and clear it quicker. The water has lightened from dark green to sea green and sometimes looks bluish. And I can now see the second step on the pool ladder.

    So now I am wondering if I need to be backwashing more often. Using DE definitely makes the pressure rise. How long can I let it be a bit higher after adding DE? Am I getting benefit of better filtration if it is at the higher pressure?
    dE is usually used to clear up the last little bit, when the green is gone but you aren't quite clear. You should backwash when your pressure is 25% over the normal clean pressure.
    26' X 52" Intex Ultra Frame. Intex Sand Filter
    26' X 52 Intex Ultra Frame Install
    You can lead a horse to (clear) water, but you can't force him to swim in it!

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