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Thread: Queston on vinyl liner discoloration

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    Queston on vinyl liner discoloration

    Hello! Fred here....

    Quick history. I am a new pool owner of about 3 weeks. I am grateful to find this site and have been reading posts religiously. I am following the BBB method and feel it is going well.

    The pool I have sat for a year with no upkeep. It was a green mess. We have, however, gotten the water very clear. Let me post my levels and I will ask my question!

    TC - 4
    FC - 4
    TA - 200
    PH - 7.4
    TH - 350
    CYA - 70
    16 x 32 - 3ft - 8ft depth, I am figuring approx 22k gallons

    When the chlorine level gets to the 1 - 1.5 level, I have three stains that appear in the deep end, roughly 2 ft diameter in a irregular pattern. When I raise the chlorine level they fade and go away, but as soon as it drops to 1 they come back. I am now on my third day keeping the chlorine at a high level and plan to continue until tomorrow. On monday I added 7.5 gallons of 6% and have added that same amount each day. I add the chlorine in the evening and test the next evening before I add more. The level comes down to 4 - 5 by the end of the day.

    Besides these three stains (which I hope the chlorine treatment will take care of), the liner has a dingy, dirty look over most of the pool. This dinginess does not brush off. The transition areas where the floor turns into a wall seem to be brighter than the floor or walls. The thing I noticed is that when I brush the liner and remove dirt or sediment has collected on the floor of the pool, where that dirt was is a brighter blue. The shape of the dirt or sediment is left in the liner as a bright blue shape. If dirt collects on a seam, when I brush the seam it is a nice blue seam. I have a feeling under this dinginess is a bright blue liner, I just don't know the next step to take. That is my question.... what should I do next?

    Thanks for all the helpful posts.
    Fred

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    JasonLion's Avatar
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    Your TA is quite high and you calcium is on the high side of the normal range, so you are very close to calcium scaling. It won't take much of a PH rise to start scaling, and that might be what you are seeing. Most chlorine sources cause some PH fluctuation, it wouldn't take a whole lot to do it.

    Whatever is happening you need to bring your TA down. This is done by lowering your PH to between 7.0 and 7.2 with acid and then aerating the pool to bring the PH back up. Repeat this process till your TA is down to perhaps 120. The lower PH and lower TA might also help the stains/dirtiness, which would be interesting to know.
    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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    Mine has done the same thing this year

    Mine has done the same thing this year, and I know what color my liner is (I put it in 2 years ago). For some reason, this year when I add water to the pool the color gets darker - til it is a duller color blue - almost brownish. It wont brush off either, just as you say. I have been told it is rusted iron. I tend to believe this bc when i let the Chlorine levels get a little lower - around 1, I will put in some of the metal remover (sequestering agent). In no time it clears up and is blue. The problem... it is coming back constantly when I add water, and the Chlorine level is high. SO my guess is you have the same issue, but it will come up with metal remover.
    5K gal QS AG soft blue pool, 1500 gph pump

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    Thanks for the tips. I will start the aration. The only way I have at the moment is to turn my return jets upward. I will look into other options, perhaps a fountain of some sort.

    I do want to try the metal remover. Can you give me a brand recommendation?

    Thanks
    Fred

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    JasonLion's Avatar
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    Jack's Magic Purple (salt) or Pink (no-salt) Stuff and Proteam's Metal Magic are all highly recommended.

    There are a couple of things you can do to narrow it down, if you want, before spending the money on one of those. Rubbing a stained area lightly with crushed vitamin C tablets and rubbing an area lightly with a trichlor puck and reporting the results will narrow it down a lot. If the vitamin C fixes the problem locally then the sequesterant is very likely to help. If the trichlor helps then the sequesterant probably won't help. If neither one of them works there are other things to explore.
    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

  6. Back To Top    #6
    Another way to speed up the aeration is to insert small pieces of garden hose (12" long or so) into the returns, then wire tire the top end to an empty water bottle to keep it floating above the surface and walla-Instant Red Neck Waterfall.

    Dave

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    Re: Queston on vinyl liner discoloration

    Quote Originally Posted by FredK
    ....When I raise the chlorine level they fade and go away, but as soon as it drops to 1 they come back.....
    If it were a metal stain, It would be the opposite-When chlorine increases, so would the staining. My best guess is that you have some sort of algae, most likely persistent black algae, that never really gets destroyed by the increased chlorine levels. I'd try rubbing the trichlor puck on it first as Jason suggested and if it fades, proceed with "shocking" (See "Ben's Best Guess" link at the bottom of Jason's post) and lot's of brushing & vacuuming all the while maintaining shock levels for a couple of days. Just my $.02 worth...

    Dave

  8. Back To Top    #8
    Thanks for the quick posts. I think I have a game plan. Tonight start my areation (...redneck waterfall, to lower my TA. (which needs to be done anyway) and test the stain with the Vitamin C or Puck. Once that test is done, then proceed to treat with either Jack's stuff or longer shocking sessions. I will try to take a picture this weekend. Will keep you posted.

    Thanks
    Fred

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    Remember to lower the TA you have to get your pH to about 7

    Remember to lower the TA you have to get your pH to about 7.0 and then Aerate. I used a jet fountain like you said... I have seen many different designs... If you are used to working with PVC, you can 90 degree out of the water. I saw one guy who put a cap on it and drilled a bunch of hole in the cap to make it shoot out of the end. If he is also on this forum he could post you a picture. Just be creative!

    I am interested in your results. Let us know. It is interesting that both of us have/had high TA (Mine was 210) and may be having metal problem (I am - you are yet to be determined). Good Luck!
    5K gal QS AG soft blue pool, 1500 gph pump

  10. Back To Top    #10
    Hello Folks,

    I was able to take a picture of the liner to post. I did the Vit C test and also the Puck test. Neither seemd to budge the dingy areas on the liner. These areas seem to be concentrated only on the bottom of the pool, not the sides.

    After having the pool at 20+ ppm chlorine for three days, I let the chlorine go back down. Well at 2 ppm, the three large stains came back. I have added another 5 gallons of 6% yesterday and the stains lightened, almost gone.

    I will post a set of levels tomorrow. Take a look at my pic.

    I saw in the stickies where Chem geek posted that at 70 cya the best guess for Yel/Mstrd shock was 40+ppm. Would it be alright to try that with a vinyl liner?

    Thanks ... will post more detail tomorrow.
    Attached Images Attached Images

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    Fred,

    Mustard algae will brush off your pool surface almost like dust....aren't you saying the stains are fixed in place? If so, that's not mustard algae.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    You are correct, I just got through brushing and it didn't make a bit of difference.

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    Fred,

    I wish I could help identify that staining but I cannot. The pool was neglected for so long, I suspect it's something deposited from the gunk on the bottom and has simply bonded to the bottom of the pool. This is a WAG, but the color change could indicate the chlorine is having a positive effect and will eventually eliminate it.

    I would bring the rest of my numbers in line (your Chlorine is too low) and swim the rest of the Summer and ignore the stains.......(I know, I know, that's going to be tough....not sure I could take my own advice).

    From time to time, I'd swim down and take a natural bristle brush to it and see if you can't make some progress. I wouldn't be surprised if they're not gone in a month or so but you must get your water chemistry squared away. Keep us posted....very puzzling problem.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  14. Back To Top    #14
    Quote Originally Posted by JasonLion
    Jack's Magic Purple (salt) or Pink (no-salt) Stuff and Proteam's Metal Magic are all highly recommended.

    There are a couple of things you can do to narrow it down, if you want, before spending the money on one of those. Rubbing a stained area lightly with crushed vitamin C tablets and rubbing an area lightly with a trichlor puck and reporting the results will narrow it down a lot. If the vitamin C fixes the problem locally then the sequesterant is very likely to help. If the trichlor helps then the sequesterant probably won't help. If neither one of them works there are other things to explore.
    ]

    I don't know if rubbing a trichlor puck on a vinyl liner is exactly the best way to fix this situation. I mean you might as well just pour a gallon of muriatic acid on the steps if you are gonna do this.

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    frustratedpoolmom's Avatar
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    Specifically to the three stains on the bottom....I think it's black algea. I have the same issue, when chlorine is high the stains fade, but they ALWAYS return when chlorine drops. The pool stealer will try to sell you a product that supposedly will "treat" the algea. The instructions involve shocking the pool. What a shock... but as always, when the CL drops, the stains return. This concurs with the above post, if it was metal, they would not dissapear with shocking. I was told the replacing the liner is the only option. I've decided I can live with it.

    BTW, IMO I don't see anything wrong in your pictures. Maybe you have a case of Pool OCD? Teee Hee....

    At some point we all have to let our obsession go and just enjoy the pool. If the readings are good and the water is clear, just go swimming and have a beer/martini. Its going to be 95 here today, me and my stains will be in the water!
    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

  16. Back To Top    #16
    mbar's Avatar
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    Yes, it could be algae that has grown under the liner - if you have a high water table, and the water got under the liner, it could form. There is no way other than treating the algae under liner to get rid of it . It lightens up with high doses of chlorine, but it can't be killed through the liner. If you get the liner replaced, make sure there is proper drainage, or a bottom that will not allow algae to grow, before the new liner is installed.
    16x33 fiberglass pool sand filter

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