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Thread: Rust stains on built in fiberglass steps of IG pool

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    Rust stains on built in fiberglass steps of IG pool

    I have an 8 year old IG pool with built in fiberglass steps. I've noticed that over the last couple years that round black stains about the size of a dime or a bit smaller, are starting to appear on the steps around the edges where the steps meet the vertical wall of the fiberglass steps. I assume that there is some kind of hardware under the steps, buried under concrete, that are rusting through.

    Has anyone experienced this and is there anything I can do to stop this bleed through?

    I can post pictures if that would help.

    Thanks

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    JasonLion's Avatar
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    Re: Rust stains on built in fiberglass steps of IG pool

    Try placing a vitamin C tablet on one of the stained areas and see what happens.
    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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    Richard320's Avatar
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    Re: Rust stains on built in fiberglass steps of IG pool

    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: Rust stains on built in fiberglass steps of IG pool

    I will try the vitamin C tablets, but the pictures look nothing like the stains I have.

    Here's a picture


    20140524_192202(1).jpg

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    Butterfly's Avatar
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    Re: Rust stains on built in fiberglass steps of IG pool

    Do you have poor water circulation in that area?

    A full set of test results would help us. We need:

    FC
    CC
    TA
    CH
    CYA


    How do you normally chlorinate the pool?

    How often do you brush the pool? Does brushing the spots make any difference?
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

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  6. Back To Top    #6

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    Re: Rust stains on built in fiberglass steps of IG pool

    Butterfly,
    The pool is an 18k gal vinyl.
    Water supply is a good clean muni water supply. I live in the water rich finger lakes/great lakes region.

    I'm fairly militant about keeping my chems in check. Although occasionally I might forget and let the CL go to 0.

    FC = Typ maintained at 3-5ppm. If I shock I run it up to around 10-15ppm depending on the CYA level.
    CC = it's zero every time I check it.
    TA = ~70 today (I maintain in the 60-100 range)
    PH = 7.6
    CH = I haven't checked it in a while but it was on the low side. From what I'v heard this isn't an issue for vinyl. I can test it now if you think it's important.
    CYA = right around 30 now.

    Virtually all of my CL comes from 12.5% liquid. I use around 10lbs of 3" tablets in the chlorinater per season.

    I don't brush often unless I have an algae issue, but I do run an aquabot.

    I've tried scrubbing those marks with a magic sponge and it does nothing.

    Thanks

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    Re: Rust stains on built in fiberglass steps of IG pool

    Bump-- Any takers on root cause of my issue and possible solutions?

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    Butterfly's Avatar
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    Re: Rust stains on built in fiberglass steps of IG pool

    Did you try the vitamin C tablet ?
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

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    Butterfly's Avatar
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    Re: Rust stains on built in fiberglass steps of IG pool

    Well, it could be cobalt spotting.

    Even tho the vinyl doesn't care about low CH, fiberglass does.

    We recommend 220 to 320 CH for a fiberglass pool, and this may be needed for the FG steps.

    Let us know how the vitamin C tab works.
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

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    Re: Rust stains on built in fiberglass steps of IG pool

    Butterfly,
    Thanks--- I'll get some vitamin C and give it a try and report back.

    I'll also work on boosting the CH based on what you said about fiberglass. Are there less expensive alternatives to boosting CH or is the pool store the only place to get the stuff?

    Thanks

  11. Back To Top    #11
    Butterfly's Avatar
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    Re: Rust stains on built in fiberglass steps of IG pool

    Get cheapest vitamin C tabs. Some of the others have a smooth outer covering which you might have to crush up to use.

    Based on where you live, you should be able to find some easily. Scroll down to Calcium Hardness for info:
    http://www.troublefreepool.com/conte...pool-chemicals
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  12. Back To Top    #12

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    Re: Rust stains on built in fiberglass steps of IG pool

    The vitamin C trick is genius! The black stains are completely gone where I put the uncoated tablets. Thank you so much!!!

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    Butterfly's Avatar
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    Re: Rust stains on built in fiberglass steps of IG pool

    Quote Originally Posted by waterdog View Post
    The vitamin C trick is genius! The black stains are completely gone where I put the uncoated tablets. Thank you so much!!!
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

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