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Thread: Rust blooms behind liner

  1. Back To Top    #1

    Join Date
    Sep 2013
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    Rust blooms behind liner

    16x32 19K gallon IG with a vinyl liner. Liner replaced ~5 years ago. Galvanized knee walls had some rust. They pretty much just put foam sheeting up right over the rust from what I know. Last year I noted what seemed to be rust blossoming behind the vinyl liner directly below the skimmer (skimmer, outlet and inlet were all replaced then too...plumbing wasn't, but it is all like flexible heavy duty radiator hose, which they said was the best thing to have up here). I called the outfit that put it in, but they were too busy closing pools to send someone out. So I just checked the screws and snugged them up a little, thinking perhaps that the cold weather had some impact. No significant water loss noted by the way.

    This year I didn't notice any significant water loss, excepting during one brutally hot week in July. My filter leaks a bit too at the clamp so I didn't think anything of it. Just notices lots more rust blooms, further to the left of the skimmer (standing above it. Not just two, but more like a half dozen (two original ones don't seem to have returned and there aren't any just below the skimmer, for what that is worth.. At this point I need to fix it if possible and close the pool.

    In an aside, my test strips say my water is too hard. I looked and it seems like the only cure is to do a partial water change. I have a lot of iron in my well water, but I usually condition the water that I put into the pool. I also pump rain water off the cover into the pool to change it up a bit.

    My pool just has grass around it and a few patio blocks, so it is possible that the wall is getting wet from behind and rusting from there. However, it is also possible that the skimmer it leaking and that chlorinated water is traveling laterally from the skimmer to attack the wall. However, If that is true it should hit the foam...but it may be that the interface between the foam and the skimmer wasn't constructed to keep the water off the walls like that.

    I was thinking about trying to change the skimmer gasket (last year I tried the food coloring leak test but really didn't find anything), but it seems that isn't the way to go. So, based on what I have seen recommended should I drop the water level below the skimmer, silicone the interface between the gasket and the face plate and the skimmer box, then leave the water level down below this skimmer for the winter? I could even take it down 18-24 inches because of the hardness and then fill it back up a bit, putting rain water under the cover to do the rest.

    Note that I always put a plastic bottle in the skimmer in the winter and there is no evident damage to it.

    Thanks in advance for the help!

    BobM
    BobM
    16x32 IG Vinyl Liner ~19K gal
    built 1964 Liner (2008), foam over galv knee wall
    3/4 hp pump (2013) 90sq ft StaRite cartridge

  2. Back To Top    #2
    linen's Avatar
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    Re: Rust blooms behind liner

    Welcome to tfp, 64dartgt

    Looks like no one has answered this, and I hadn't yet since I wasn't sure what I would do.

    I does sound like you have a small amount of water leaking at the skimmer gasket. You could try and replace it with a new butterfly gasket that should seal the whole area well. While you are in there you can take a peak down the wall and see how bad the rust is. Silicone can work, but I find it is tricky to use it and not make the issue worse with expansion and contraction, etc.

    Is the rust showing up on the outside?


    Quote Originally Posted by 64dartgt
    In an aside, my test strips say my water is too hard. I looked and it seems like the only cure is to do a partial water change. I have a lot of iron in my well water, but I usually condition the water that I put into the pool.
    You can probably live with high calcium levels in a vinyl pool, but the iron may be problematic. How high is the calcium hardness (CH) level? Note: test strips do not test for CH only total hardness which is not too helpful. The test strips are for the most part not reliable or accurate enough for proper pool chemistry. When you have filled in the past do you get iron staining or tinting of the water? If you haven't then I would just use the water as is.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

  3. Back To Top    #3
    techguy's Avatar
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    Re: Rust blooms behind liner

    I would say if you have rust behind the liner that was not addressed (sanded off and painted over with rust-neutralizing paint, replacement penal patches) you need to drain to a pint where you can address these areas.

    Are they just below the skimmer, only at the cove, only at a certain point?, or under a deck? I could not determine exactly where in the pool this was occurring.
    -- Guy --
    10K gallons in 21' Round 52 inch wall Aqualeader AG, Hayward Power Flow LX 1.5 HP pump motor, Hayward Perflex EC50AC DE filter w/Cellulose, Wide mouth skimmer, 2013 new Diver Dan (craigslist) to replace the faded old Hayward AquaBug. TF-100

  4. Back To Top    #4

    Join Date
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    Northborough, MA
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    Re: Rust blooms behind liner

    The pool is an in ground vinyl lined pool that is dug with sand under the line and a three foot high galvanized steel knee wall. I am guessing they were relying on the foam they installed to cover the rust. There is no way to access the back of the walls without extensive digging. The rust is to the right of the skimmer coming form the metal wall and seems to be significant enough to be pushing the foam up to form rust bubbles about three inches in diameter. There is only earth around the pool so water is no doubt in contact with the back of the metal wall as well. This time of year there is almost no way I can get a pool contractor to look at it. They are closing pools at $300-500 a pop at the moment.
    BobM
    16x32 IG Vinyl Liner ~19K gal
    built 1964 Liner (2008), foam over galv knee wall
    3/4 hp pump (2013) 90sq ft StaRite cartridge

  5. Back To Top    #5
    techguy's Avatar
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    Re: Rust blooms behind liner

    $300-500 to close a pool? Man... I am in the wrong business.
    -- Guy --
    10K gallons in 21' Round 52 inch wall Aqualeader AG, Hayward Power Flow LX 1.5 HP pump motor, Hayward Perflex EC50AC DE filter w/Cellulose, Wide mouth skimmer, 2013 new Diver Dan (craigslist) to replace the faded old Hayward AquaBug. TF-100

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