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Thread: Brown Discoloration on Light Ring

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    Brown Discoloration on Light Ring

    Hi all,

    My water chemistry went out of whack while I was not paying too much attention to testing, as well as "stationary" pool shark cleaner while waiting for replacement pods, feet and wings.

    First signs were black/brown discoloration of the stainless steel light ring and black algae spots particularly on steps and near bottom of walls.
    Added algaecide which helped a little for a few days and noticed that the algae started coming back. Added a second dose (making for a years supply according to the manufacturer - in just a couple of weeks.)
    Also cleaned out the filter and vacuumed the pool only to note the return of the algae.

    Testing showed FC =0, PH =8 etc.
    Placing Pool pilot in boost mode generated a "clean cell" warning.

    The cell was found to be completely clogged and took several iterations of 4:1 acid to completely clean it.

    The water is now balanced, the algae is gone, but the discoloration of the light ring remains.
    It is not removed by brushing with a stainless steel brush. Close examination shows it to be brown in color.

    Can someone please tell me what is this discoloration and how do I get rid of it.

    For what it is worth, the light may be removed from the pool and placed on the deck for testing or treatment if that is considered easier than treating the pool water.

    There are also a few brownish patches on the floor of the pool which are rather unsightly given how sparkly the water is right now. I will try to post a picture of those patches later but hope for help with the light ring in the meantime.

    Thanks
    --------------------
    10k gal conc. in-ground
    DiamondBrite cool blue
    Pentair Cartridge filter
    Hayward 3/4 HP pump
    Pool Pilot Digital 220
    Hayward Navigator Pool Shark

  2. Back To Top    #2
    JasonLion's Avatar
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    Re: Brown Discoloration on Light Ring

    Try holding a vitamin C tablet against one of the discolored areas for 30 seconds and see if that improves things.
    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

  3. Back To Top    #3

    Re: Brown Discoloration on Light Ring

    Will try that tomorrow after visiting the drug store.

    What is the chemistry involved in "stain" + "vitamin c".

    What are the potential results and what do you do in case it comes off or it don't?
    --------------------
    10k gal conc. in-ground
    DiamondBrite cool blue
    Pentair Cartridge filter
    Hayward 3/4 HP pump
    Pool Pilot Digital 220
    Hayward Navigator Pool Shark

  4. Back To Top    #4
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Brown Discoloration on Light Ring

    Vitamin C, ascorbic acid, is a reducing agent, which donates an electron to the iron in the stain, if the stain is an iron stain, which allows the iron to go back into solution. It will also work at least some of the time with other metal stains, though most reliably with iron. If the stain goes away, it is most likely an iron stain and can be removed with either a local or whole pool ascorbic acid treatment. If the vitamin C does nothing we know it isn't iron, but otherwise need to start over and try something else.
    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

  5. Back To Top    #5

    Re: Brown Discoloration on Light Ring

    Jason,

    Finally got into the pool today and tried the Vitamin C.
    I noted a bit of silver showing through after holding the tablet for about a minute.

    I then removed the light from the niche and placed it on the deck. It was layer with a chocolate brown coating that was quite adherent.

    Considering that you said it was an acid/metal reaction, I tried a bit of muriatic acid diluted about 50% and the coating fizzed and washed off as a black residue.

    All the chrome was still there undamaged and is bright and sparkling again.

    However, I would still like your ideas on what this was.
    The algaecide I overdosed the water with was Lo-Chlor Pool Algicide with copper sulphate Pentahydrate as active ingredient.

    The stain on the floor did not respond to the vitamin C. Have pictures but will upload in a subsequent post.
    --------------------
    10k gal conc. in-ground
    DiamondBrite cool blue
    Pentair Cartridge filter
    Hayward 3/4 HP pump
    Pool Pilot Digital 220
    Hayward Navigator Pool Shark

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    Mod Squad Bama Rambler's Avatar
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    SouthWest Alabama
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    Re: Brown Discoloration on Light Ring

    Since the acid made it fizz, it was probably a little scaling with some imbedded copper in it. It's common for copper to tarnish black.

    Bottom stains are usually tannins from leaves, etc. You can try holding a trichlor tablet on the stain to see if it does anything to lighten it.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    duraleigh's Avatar
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    Apr 2007
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    Re: Brown Discoloration on Light Ring

    Somewhat off topic, but using algaecide for an algae bloom seldom works well. You need chlorine...nothing else.

    Pool School will get you some good info and then ask lots of questions.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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