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Thread: Fighting Metal Stains - Getting Ready to Use Ascorbic Acid Tonight.....

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    Question Fighting Metal Stains - Getting Ready to Use Ascorbic Acid Tonight.....

    I have metal stains on my pool liner. I tested with a crushed up Vitamin C tablet and confirmed what they were, now it's time to perform the ascorbic acid treatment and I just wanted to make sure I had my plan right before starting when I get home from work today. Here's where I am:

    FC - 2.0
    CC - 0.5
    pH - 8.0
    TA - 120
    Ca - 190
    CYA - 55
    30k inground saltwater pool with vinyl liner

    This morning I turned off the SWG and dumped one quart of Polyquat 60 into the pool. By the time I get home I'm sure the FC will be down close to 0. My plan is as follows:

    1 - Put multiport on recirculate and turn pump on continuously (24/7)
    2 - Add about 100 oz of muriatic acid to bring pH down to 7.2
    3 - Wait 30 mins
    4 - Apply @ 2 lbs. of ascorbic acid
    5 - Wait 1 hr to see if stains disappear, repeat steps 4 & 5 until stains are gone
    6 - Add sequestering agent
    7 - Put multiport on filter
    8 - Wait 24 hrs
    9 - Rebalance water - bring pH up to 7.2 and use bleach to bring up FC to 5
    10 - Turn on SWG and set to 80 (where i typically keep it)
    11 - Put pump back on timer
    12 - Wait 1-2 weeks
    13 - Bring pH back up to 7.5
    14 - Use sequestrant weekly from here on out

    Sooooooo, what am I missing? Did I add enough polyquat? Should I turn my SWG back on when I said I should? Any tips or tricks?

    Help is greatly appreciated....
    30,000 Gallon Inground, Vinyl Liner
    DE Filter & Pentair IC40 SWG
    Pentair Legend Platinum w/ PB4 Booster
    Pentair Kreepy Krawler Prowler Robot

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    Re: Fighting Metal Stains - Getting Ready to Use Ascorbic Acid Tonight.....

    Also, I think the source of the metal that's causing my staining is inside my skimmer assemblies (2). I can see definite rust stains in there and both skimmers have prominent stains around them. It seems like there is metal in there but I can't see it. Do the skimmer assemblies typically have metallic parts? If that's the source, is there anything i can do to alleviate the issue?
    30,000 Gallon Inground, Vinyl Liner
    DE Filter & Pentair IC40 SWG
    Pentair Legend Platinum w/ PB4 Booster
    Pentair Kreepy Krawler Prowler Robot

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    Mod Squad pooldv's Avatar
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    Re: Fighting Metal Stains - Getting Ready to Use Ascorbic Acid Tonight.....

    Just in case you don't have this, Ascorbic Treatment to rid Pool of metal stains

    No, skimmers do not typically have metal in them and would not be a source of metals in the water unless your pool is very old. The most common sources of metal are well water, algaecide that contains copper, "mineral sanitizer" systems and copper dissolved by PH at 7.0 or lower from heaters or old plumbing.
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    Re: Fighting Metal Stains - Getting Ready to Use Ascorbic Acid Tonight.....

    Sounds like you have the method down pat. Why do the treatment now during swim season when the FC will have to be low and warm water temperatures? One you'll have insufficient santizer to swim and two much greater risk of algae bloom with warm water than later in the season. If you get a bloom you'll be slamming and undoing all the time and $ spent

    ETA the skimmers are made of a Pvc that seems to be a magnet for iron stains. Your return eyeballs are probably dark brown inside as well.
    If we could figure out the exact Pvc compositions of those plastic bits I'd have sheets of draped in my pool and slam away
    30k in ground vinyl lined pool surrounded by decking in the woods.
    Hayward sand filter circa mid 80's
    If there is a way to do things less expensively and yield a superior product I am all ears

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    Re: Fighting Metal Stains - Getting Ready to Use Ascorbic Acid Tonight.....

    Basod - too late to turn back now. I did the treatment yesterday after work (before you posted) and the results are quite substantial. The ascorbic acid lifted almost all the stains from my liner (with the exceptions of some staining around the skimmers). So far the water still looks crystal clear and I don't see any signs of algae so the polyquat must be doing its job. I took some readings this morning and here's what I got.

    FC - 0
    TA - 70
    pH - 7.1

    So tonight I'm going to bring up the pH a tad and then add enough bleach to bring up my FC to 5 (I'll do it over the course of 3-4 hrs to bring it up somewhat slowly). Then I'll turn on the SWG tonight.

    Once the chlorine is added, is there any reason my kids and I shouldn't swim????
    30,000 Gallon Inground, Vinyl Liner
    DE Filter & Pentair IC40 SWG
    Pentair Legend Platinum w/ PB4 Booster
    Pentair Kreepy Krawler Prowler Robot

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    Mod Squad pooldv's Avatar
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    Re: Fighting Metal Stains - Getting Ready to Use Ascorbic Acid Tonight.....

    It is safe to swim when
    FC is above minimum for your CYA, FC/CYA Chart
    and below shock level
    PH is between 7.2 and 7.8
    And the water is clear

    I would be inclined to turn on the SWG now. It will slowly raise your FC and raise your PH a bit too.
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    Re: Fighting Metal Stains - Getting Ready to Use Ascorbic Acid Tonight.....

    Another idea where your stains are coming from may be your own city water supply. My small town has a water report twice a year and iron is always listed on the report. I have a white plastic jug I use for watering some small plants with and that jug also has the same color iron stains as my pool. Just a thought.
    19,000 gal - Vinyl IG - Sand filter -1.5hp. - Taylor k 2006 - Loop Loc cover

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    Re: Fighting Metal Stains - Getting Ready to Use Ascorbic Acid Tonight.....

    Just keep an eye on the FC, adjust after bleach addition every few hours, took me ~72hrs - some see many more days before they stop losing FC to AA neutralization

    You're in a balancing act now, FC not too high, pH as low as possible, sequestrant doses weekly.

    I've been working on getting to a point where sequestrant isn't required -through controlling/filtering fill water, removing stains and getting them out of the pool in one shot, and polishing continuously for preventive treatment
    30k in ground vinyl lined pool surrounded by decking in the woods.
    Hayward sand filter circa mid 80's
    If there is a way to do things less expensively and yield a superior product I am all ears

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    Re: Fighting Metal Stains - Getting Ready to Use Ascorbic Acid Tonight.....

    You say add sequestrant weekly, but I thought it said monthly (maybe I'm confusing this with something else). How much should I add weekly/monthly for my 30,000 gallon?

    Still losing FC, hopefully that will end soon as I have to leave town next week and the wife's not quite as diligent with regards to the pool. Maybe I'll give it another dose of polyquat before I leave, but how much??? I put in a quart of polyquat 60 prior to starting the AA treatment.
    30,000 Gallon Inground, Vinyl Liner
    DE Filter & Pentair IC40 SWG
    Pentair Legend Platinum w/ PB4 Booster
    Pentair Kreepy Krawler Prowler Robot

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    Re: Fighting Metal Stains - Getting Ready to Use Ascorbic Acid Tonight.....

    The dosage rating for maintenance will be a balancing act on your part, but the label on whatever you're using(you didn't state the product) should give a week/month dosing.
    It will take more in the beginning as you're bringing FC back to normal levels.
    Leaving for a while in the middle of trying to play this balancing act is why I posted above on waiting until the water is cooler.... Hey we all live and learn
    Whatever Polyquat 60 recommends as a maintenance dose should help, but it isn't going to sanitize while away just help prevent the algae growth - not guarantee no algae growth
    30k in ground vinyl lined pool surrounded by decking in the woods.
    Hayward sand filter circa mid 80's
    If there is a way to do things less expensively and yield a superior product I am all ears

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