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Thread: Liner Installation - Dewatering

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    Liner Installation - Dewatering

    Well my journey to new liner for my 16x36 inground pool has been a nightmare

    1) Liner comes out, find ground water coming back in when you get to about 2 feet from deep end
    2) find that well points were sunk during construction, however cannot find where they terminate. Probably under my concrete patio
    3) lines cut along the wall, new hose snaked up behind walls to new exit point at deck level. Pumping begins
    4) deep end hits water free while pumps are running, sand is smoothed, liner goes in, water starts getting pumped in
    5) power goes out in our entire neighborhood, pumps shut down, groundwater seeps back in, liner installation ruined
    6) pull the liner out and start over however now that evening, neighbor aroudn the corner complains about water coming down street from pumps
    7) town shuts the crew down, now we need dewatering permit
    8) 3 weeks later, permit FINALLY approved, now we're starting again, and neighbors cant complain about nothing haha

    However got a few questions from you pool gurus.....

    My liner installer plans on pumping to the street (per the permit instructions) until the liner goes in, at which point they then plan on pumping the ground water back into the pool so that no more water is being pumped off property, and it helps fill the pool quickly. He said as long as its coming out clear and clean, it shouldnt be an issue. Is he correct?

    That being said, i'd like to only pump ground water in until we hit the proper point of hydrostatic pressure where we can shut the punmps off and finish filling with hose water. I'm assuming since we only had about 1.5 to 2 ft of ground water in the deep end, once we fill to the point where the deep end levels out to the shallow end, we should have no problem with ground water seepage since the pressure should be enough to hold it back while we finish filling with garden hose?

    Or should i just us the ground water entirely since it will pump pretty quickly and just chemically stabilize it once everything is said and done. Let the filter do its job filtering out particles, and vaccum to waste anything that settles to the bottom?

  2. Back To Top    #2

    Join Date
    Oct 2011

    Re: Liner Installation - Dewatering

    Without knowing the quality of the ground water, there is no way to tell what might be better. If you have a test kit, you could take a look at the ground water and make a determination, but if it is really hard (much harder than the house supply) I would want to use as much house water as possible.
    20x44 IG vinyl. Intelliflo, Pentair Cartridge Filter (420ft^2), Raypac 336K, Kreepy Krauly

  3. Back To Top    #3

    Join Date
    Jul 2012
    SE Georgia

    Re: Liner Installation - Dewatering

    I would take the water somewhere to get it tested. Make sure they test for iron and other metals. We were going to do the same thing but there was so much iron in the water that it would have been a nightmare to get cleaned up. I was told it would turn the water brown when I added chlorine. Either way, I did not want to take the chance considering the water from my community well had very little to no iron and I am un-metered. I was putting some new water faucets in my back yard around the pool so before actually put in the faucets, I put a temporary open ended pipe going into the pool to fill it up. Pool filled in around 18-19 hours... Not bad for 23000 gallons... (Although, we had virtually 0 water pressure in the house while the pool was filling.)
    Our Pool Build! (Done) 18x36, IG Vinyl... All Equipment is Pentair... EasyTouch with IC40 SWG, Clean and Clear Plus 420 Cartridge Filter, Intelliflo VS pump.

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    Divin Dave's Avatar
    Join Date
    Oct 2013
    Longview, Texas

    Re: Liner Installation - Dewatering

    Iron in the water will be your main problem if there is any. Most pool stores can test for metal present in the water. Calcium hardness should not be a problem in a vinyl liner pool unless its really really really high.

    If there is no iron, I would fill half and half... if not too dirty maybe even fill it full and save on your water bill. EIther way is still gonna be a good bit of filtering and vacuuming.
    If there is iron, certainly do not put any more in there than you can tolerate because you will just have to somehow deal with it and wont be much fun to do that.
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge. Experience- it's what's learned just after you needed it most !!

  5. Back To Top    #5

    Re: Liner Installation - Dewatering

    Well got the ground water tested before the liner was put in (just put the test bottle in front of the discharge hose) and brought it to get tested. Read 4-5ppm Iron content with a PH of around 6.8.

    So i ended up using the ground water only to fill about 2-3feet worth of water into the pool to start counteracting the groundwater seepage and develop some hydrostatic pressure, and then shut it off and started filling with only the garden hoses. SO i'd say by the time the pool is finished filling it will be 3/4 tap water, and 1/4 ground water, which should be controllable levels of iron. A couple CuLator bags in the skimmers and some sequestrants to remove whatever is left of the iron. Will test the water once the pool is fully filled before starting to adjust the chemical balance and turn on the filter.

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