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Thread: Shock level questions

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    98xc600's Avatar
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    Shock level questions

    I'm in the middle of battling something in my pool and was wondering, at what level should you shock it at if you don't know what is causing CC of 1 and FC to drop overnight? I have no indication of algae. So do I stay at normal level of shock which for me is 16 or do you go to 27 for Mustard algae because you don't know if that's it or not? Is mustard algae even a problem in northern states? and do you leave a solar cover on at shock level or take it off?
    I was thinking leaving it on so I don't burn up as much FC, but if you take it off you would be burning up some of the CC. So what do you do? or am I putting way to much thought into this.
    16' by 32' cornelius AG vinyl liner, 6' deep end, 14500 gal.
    Hayward 250 Lb sand filter
    Hayward 40 GPM pump
    2-2' by 20' sun grabber solar heater.
    4 gal Liquidator. BBB

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    frustratedpoolmom's Avatar
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    Re: Shock level questions

    How much FC would you normally lose in a day? Say 2-3ppm? I would add that to your shock level, so go to like 20ppm and then leave the cover off....give that a try? No need to shock to Mustard level if you can't see it to identify it.

    Or, wait till tonight and shock tonight to 16, remove the cover in the morning? I'm not sure it matters either way you do it....obviously you will lose more of your shock level to sunlight if you shock during the day...
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    JasonLion's Avatar
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    Re: Shock level questions

    If you are having CC issues, it is better to leave the cover off during the day.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    98xc600's Avatar
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    Re: Shock level questions

    Quote Originally Posted by frustratedpoolmom
    How much FC would you normally lose in a day? Say 2-3ppm? I would add that to your shock level, so go to like 20ppm and then leave the cover off....
    I lose about 3-4ppm per day, This is what I've did so far.
    The last 1-1/2 months
    FC 6
    CC .5 never went above or below this
    Tues night add 3 gallons bleach put solar cover on
    FC 17.5
    CC .5
    Wed morning
    FC 15.5
    CC 1.0
    add 1 gallon bleach
    FC 18.5
    CC 1.0
    Wed afternoon
    FC 17
    CC 1.0
    Wed night
    add 1 gallon bleach
    FC 20
    cc 1.0
    Thurs morning
    FC 19
    CC 1.0
    add 1/2 gallon bleach
    removed cover at 12:00
    Thur afternoon
    FC 17
    CC .5
    added 1/2 gallon bleach
    Thurs night
    FC 18.5
    CC .75
    Fri morning
    FC 16.5
    CC 1.0


    I don't know!! Maybe I don't even have a problem but with the CC at the level there at it looks like I'm killing something. am I wrong?
    16' by 32' cornelius AG vinyl liner, 6' deep end, 14500 gal.
    Hayward 250 Lb sand filter
    Hayward 40 GPM pump
    2-2' by 20' sun grabber solar heater.
    4 gal Liquidator. BBB

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    frustratedpoolmom's Avatar
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    Re: Shock level questions

    I think you are correct in your assumption, based on those numbers. Yeah, tonight I would shock to 20 and leave the cover off all day tomorrow....see if that helps. Good luck, how frustrating!
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    98xc600's Avatar
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    Re: Shock level questions

    The more I think about this problem the more I wonder what's going on. Last year I never had a problem with the water. The PH didn't drift up or down very much, maybe once a month I would have to drop the PH, and it wasn't by much, maybe .2 Chlorine levels were fairly stable but After taking advice here about getting my TA down to the "right level" that's when it all started.

    Last year I was running a TA as high as 290, by the end of the summer it was at 230. I only had to adjust my PH 3 times last year. Heres the numbers from last year that I recorded. There were very small adjustments in between these numbers
    Code:
                  7/26/07       8/6/07      8/11/07                8/18/07       9/5/07                                                                          
                  FC 6.5        FC 3        FC 5                   FC 4           FC 5
                  CC .5         CC 0        CC 0                   CC 0           CC  0
                  P H 7.5       PH 7.6      PH 7.6 added acid      PH 7.5         PH 7.5   
                  TA 290       TA 270      TA 230                  TA 230         TA 230 
                  CYA 55       CYA 55      CYA 55                  CYA 55         CYA 55
    After spending all winter reading TFP, I decided I should lower my TA even thought my PH wasn't climbing like they claimed that it should have and I had no other problems. On 6/10/08 I start to lowered my TA from 230 to 100 and after I hit 170, my PH started to climb very fast from a 7.2 to a 7.8 in one day consistently. so I spent the next month working on my TA and PH to bring it down to the target level I'm being told it needs to be at "100" and then all this starts to happen right after I get the TA to were you people think it needs to be.
    Maybe it's just the way everything is working out at this point, but it sure seams like TA is tied into all of this some how?????????????
    16' by 32' cornelius AG vinyl liner, 6' deep end, 14500 gal.
    Hayward 250 Lb sand filter
    Hayward 40 GPM pump
    2-2' by 20' sun grabber solar heater.
    4 gal Liquidator. BBB

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    JasonLion's Avatar
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    Re: Shock level questions

    PH and TA are related in complicated ways. Your experience with lowering TA is unusual, but not unheard of. However, PH and TA don't normally have much to do with chlorine usage and algae, unless the PH is getting way out of range (less than 6.8 or higher than 8.2).
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    98xc600's Avatar
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    Re: Shock level questions

    Quote Originally Posted by JasonLion
    PH and TA are related in complicated ways. Your experience with lowering TA is unusual, but not unheard of. However, PH and TA don't normally have much to do with chlorine usage and algae, unless the PH is getting way out of range (less than 6.8 or higher than 8.2).
    Your right, I'm sure it has nothing to do with whats happening now. I wrote that out of frustration more that anything.
    I'm starting to suspect it may be the solar cover. It looks clean, but it's on and off all the time. That would allow something to grow all day long and then I put it on and the bleach has to start all over again. That would make sense as to why Ive had CC all summer! The covers never on long enough to fully kill what might be on it. So I'll give no cover a try next.

    I don't know..... Dose this sound like the ramblings of a desperate man

    If it don't, it should
    16' by 32' cornelius AG vinyl liner, 6' deep end, 14500 gal.
    Hayward 250 Lb sand filter
    Hayward 40 GPM pump
    2-2' by 20' sun grabber solar heater.
    4 gal Liquidator. BBB

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    frustratedpoolmom's Avatar
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    Re: Shock level questions

    I use a solar cover constantly and I don't have these issues. What I would suggest is shocking one night, leaving the cover on (in darkness, no sunlight to kill CC's anyway, right) but the chlorine is high and it will help sanitize the cover, if there is something there. I try to get some of the pool water on the top of the cover, to give the top a good "cleansing" I guess. If there is something on there, and you're right, the covers not on the pool "at the right time" it won't get sanitized too....gosh I hope that makes sense.

    Sorry for your frustration....

    There is something I read on here that if you are not experiencing a rise in PH, then lowering TA from the range you had isn't critical.....only go thru the process if you think it's necessary.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    Shelley N's Avatar
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    Re: Shock level questions

    98xc600 -

    What is it you are fighting? Are you having any other problems with your water or is it just the test results for the CCs and the drop in FC that have got you down? How does the water look? I had a similar experience last year, and after all was said and done, I believe I was just hyper sensitive to test results over what we were experiencing with the pool. This year, I just test for the FC and if I find I let the FC get too low one afternoon (like 3 or something--my cya is around 50) I just bring the FC that night to the top of my normal range (8), cover it and forget about it till the next day. I have had nothing but beautiful water this year, haven't shocked once and have enjoyed the pool every day. If I ever see cloudy water...I would have to take action, but last year if I noticed I got down to FC of 3, or thought I smelled CCs, I would shock for a couple days and we would loose 3-4 days in the pool yet it always looked good.
    Shelley
    Denver, CO

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    98xc600's Avatar
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    Re: Shock level questions

    I left the solar cover off all day yesterday and last night. My FC didn't drop at all and the CC level was a .5 I'm hoping the rest of the CC's will burn off during the day today and the problem is gone. I think the cover had something to do with it. Time to get a new one!!!
    16' by 32' cornelius AG vinyl liner, 6' deep end, 14500 gal.
    Hayward 250 Lb sand filter
    Hayward 40 GPM pump
    2-2' by 20' sun grabber solar heater.
    4 gal Liquidator. BBB

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    Re: Shock level questions

    Just my experience. A High FC level witll DESTROY a solar cover quickly. They fall apart fast enough- anytime I'm near or above 10 FC I take mine off. The high FC seems to make them very brittle.
    24' Round Doughboy AG.
    Usually filled with 3 kids, the wife, and occasionally the dog.

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    frustratedpoolmom's Avatar
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    Re: Shock level questions

    My experience has been different than yours, shocking with the cover on does not appear to have harmed my cheapy-blue solar cover at all, its in great shape, this is it's second season. But then, I've only shocked my pool 3 or 4 times in these last two summers.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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