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Thread: Groundwater problem with vinyl liner

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    Groundwater problem with vinyl liner

    I just opened the pool; see pictures at:
    http://www.flickr.com/photos/9826176@N07/sets/

    Hopefully you can see them.

    The problem is: groundwater is pushing the liner away from the sides of the pool. I had this problem for the last 2 years but not this bad. The last 2 times, I pumped the water out between the liner and the hard side of the pool and all was well. Is there a better way?
    Thanks for any advice.
    Bob
    25,000 gallon
    16' x32' Rectangle IG, Vinyl liner
    DE filter

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    JasonLion's Avatar
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    Re: Groundwater problem with vinyl liner

    This kind of thing happens any time the ground water level is higher than the water level in the pool. Usually if you raise the water level in the pool up to the top of the skimmer that will take care of it. As long as the bottom of the liner doesn't shift you will be fine. If the bottom shifts you need to go very slowly and make sure the bottom gets moved back into place before filling much above the ground water level.
    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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    Re: Groundwater problem with vinyl liner

    Jason,
    Thanks for your note. I've been replacing the water while pumping it out so as to try to maintain equal pressure on the liner.
    I'm not sure how to "...make sure the bottom gets moved back into place before filling much above the ground water level" you mentioned in your note?
    Thanks,
    Bob
    25,000 gallon
    16' x32' Rectangle IG, Vinyl liner
    DE filter

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    JasonLion's Avatar
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    Re: Groundwater problem with vinyl liner

    If you really have to realign the bottom it is a big project. Most of the time everything will go back into place on it's own. But if you see wrinkles forming lower down that stay in place as you fill further you need to find some way to get the liner realigned correctly.
    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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    Re: Groundwater problem with vinyl liner

    Jason,
    I get your point. The best I can do is use my pool liner brush with the pole and hope things settle down. Last year, I had about a 1' high by 8' wide bubble around drains and that went away fine. This is much worse as it involves the sides.
    Just so I'm prepared for the worst. If a lot of wrinkles remain, I assume pool would need to be drained, realign liner (or replace) and refill. My concern is that the side walls could collapse when doing this. Does this happen?
    25,000 gallon
    16' x32' Rectangle IG, Vinyl liner
    DE filter

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    JasonLion's Avatar
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    Re: Groundwater problem with vinyl liner

    When the ground water is really high you don't want to fully drain, nor would you normally need to. Lowering the water a little will float the liner again and it will be possible to move it. I've heard of using sand bags to hold sections in place while you work in other areas. Depending on how bad it gets you might want to hire a professional.

    The corners at the bottom are the really important spots. If they stay in place things will generally recover.
    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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    Re: Groundwater problem with vinyl liner

    Gotcha. Another reason to go concrete I guess.
    25,000 gallon
    16' x32' Rectangle IG, Vinyl liner
    DE filter

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    Re: Groundwater problem with vinyl liner

    Is there any chance that when your pool was built, a sump drain pipe was installed under the deep end? If it's there, the top end is probably buried very shallowly outside the deep-end deck. Here's what mine looked like before they trimmed it and buried it in the backfill (bottom of picture):
    [attachment=0:219zdt2s]Drain.png[/attachment:219zdt2s]
    If there is one, you might be able to use it to pump the groundwater out while you fix the liner and fill the pool (or just keep pumping until the ground water level falls).
    Attached Images Attached Images
    Hydraulically mundane 20x40 rectangular polymer (~30K gal.), IntelliFlo VS+SVRS pump, IntelliChlor IC40 SWCG, Pentair CCP520 cartridge filter, LED light, 2xDeck Jets, SR Smith Turbo Twister slide

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    Re: Groundwater problem with vinyl liner

    Simbilis,
    I wish I had that pump installed; never offered (who knew?).
    Since my original post, I've pumped out the water behind the liner and thank God the vinyl went back to install condition except for one or two short wrinkles (I tried to smooth them out but no go).
    Dodged another one of life's bullets!
    Thanks,
    Bob
    25,000 gallon
    16' x32' Rectangle IG, Vinyl liner
    DE filter

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    Re: Groundwater problem with vinyl liner

    Bob22, welcome to TFP!!

    I HOPE I'm wrong, but it looks like there is a tear in the liner (in your first pic of the corner all bulged out)

    If it is a tear, your pool water is exacerbating the ground water issue

    I'll be back tomorrow to see if you can confirm my suspicion.

    (I truly hope my eyes are just deceiving me!)
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

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    Re: Groundwater problem with vinyl liner

    bob22 - My brother inlaw has the same problem. He built his pool in a low area when it was dry and in year when we get alot of rain the ground water rises and pushes his liner away from the wall. He usually waits until the ground water level lowers then drains a portion of his pool and fixes the liner.
    35K IG Vinyl 20 x 40 self built pool, Hayward Pro Series High-Rate Sand Filter 31" 98gal/min, Hayward TriStar 1.85hp, Hayward 400btu heater, BBB method w/Hypo, Jazz light w/matching fiber optic rope lighting around coping w/syncronized color wheels. Concrete Paver deck.

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    Re: Groundwater problem with vinyl liner

    Thanks all. There doesn't appear to be any tears or holes in the liner. I filled it back up to skimmer level to get filtering going.
    Water level is stable and the green color is not fairly clear (19 bottles of bleach and about 2 lbs of granular Chlorine; I didn't want yellow mustard algae again!).
    I'm afraid of reducing water level too low to fix liner as I'd have to take out more than a third and I'm afraid the sides might collapse/slide in without water pressure of the pool pushing back. Perhaps it wouldn't happen, but for now at least, I can live with a few wrinkles.
    I'll post after pictures soon.
    25,000 gallon
    16' x32' Rectangle IG, Vinyl liner
    DE filter

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