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Thread: Black Bottomed Gunite - HELP!

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    Black Bottomed Gunite - HELP!

    I bought this house December after eight months in short sale. The gunite pool was unopened and uncovered for at least two, if not three, years. When I saw it in April 2012 the water was very low and the pool, apart from the shallow black water, looked good and the gunite was white. Fast forward through a snowy winter and a pool filled to the brim with black water to this weekend. The plan was to drain and acid wash it. What we found were two feet of leaves at the bottom of the pool. After the leaves were removed and the pool power washed, we discovered that the pool bottom had gone from white to black. The gunite is also a moment away from concrete, so an acid was is now out of the question. Anybody know why the pool bottom is black? Algae? Tannins? Metal (the well water here is very high in iron)? Any suggestions/solutions? Here is a picutre.[attachment=0:3jltc6k8]pool051013.JPG[/attachment:3jltc6k8]
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    Re: Black Bottomed Gunite - HELP!

    Welcome to TFP!

    The plaster is black because of both tannins in the leaves and algae. You can lump all of these together and just say "organic staining". Can't really know about metals until you test the water. If the pool is filled with well water, then it may be possible to have metals in the pool but it really isn't an issue now.

    You can go ahead and fill the pool if you like, in order to see if the pump and filter setup is working and also if the pool holds water. Or, if you're feeling strongly about going ahead with having the plaster redone, you can do that too. Your choice.

    We have seen pools such as what you describe (and worse) brought back from the dead with a good cleaning, fill, shock process, and some TLC. Although it may look bad to you now, gunite pools can survive some pretty harsh treatment and bounce back. If the plaster is good, shocking the pool may be all that you need to make the plaster white again.

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    Re: Black Bottomed Gunite - HELP!

    Replastering isn't in the budget. Someone suggested painting it with an epoxy pool paint, but painting over algae doesn't seems like a good idea. I read somewhere that cleaning it with a bleach solution before it's filled may help. What's your opinion?

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    Mod Squad jblizzle's Avatar
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    Re: Black Bottomed Gunite - HELP!

    Paint is a very temp solution, lasting only a couple years. I would try scrubbing it down with a bleach solution and maybe just having to live with some discoloration until you can replaster.

    Posted from my Droid with Tapatalk ... sorry if my response is short
    Jason, TFP Moderator
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    Re: Black Bottomed Gunite - HELP!

    We really don't suggest applying pool paint. It is very expensive for what you get and usually won't last you more than a year. And no, applying it over a surface that is less than perfectly prepped per the paint manufacturer would really just be asking for trouble.

    Here's what I would suggest, and others will no doubt have suggestions after the sun rises...but I would say that if you can fill it and run the pump, you can probably go ahead and shock and balance the water. Brush the plaster good during the process, keeping your FC high, and filtering should get things looking good. If you can make it through the season, work a little OT and scrimp, and then have your plaster redone in the off-season when it is cheaper and contractors are willing to deal, you'll save and be better off.

    Here are some links to help you. Read Pool School and look at the stickies. Get a good test kit too. The test kit is the MOST IMPORTANT part! You need a service type kit and you cannot get those in pool stores. They must be ordered online and we suggest going to tftestkits.net for the best prices.

    turning-your-green-swamp-back-into-a-sparkling-oasis-t4147.html
    pool-school/shocking_your_pool

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    Re: Black Bottomed Gunite - HELP!

    I love you! I have joined at least five pool forums today and yours is the first responsive response! I will try to post pictures in the am when I can shrink the photo.

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    Re: Black Bottomed Gunite - HELP!

    Great! We LOVE rehab photos!

    I promise that if you do what we teach here (and this is not hard stuff to grasp, really it isn't) then you will realize success. And to toot our own horn here, we don't really see ourselves as having competitors. Most other "pool forums" are lacking in honesty, science, and politeness and are frequently nothing more than a medium for product sales. We have no financial agenda and just want to help. Aside from about 5 or 6 people who were here from the get go, the rest of the nearly 50,000 members here arrived with questions and knowing little to nothing about pools. These are the ones giving out the advice now. For entertaining reading, take a look at some of our high post count and long time members profiles and find their first post. You'll see what I mean.

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    Re: Black Bottomed Gunite - HELP!

    I added a picture (albeit sideways). Would someone take a look at give me your thoughts? Thanks.

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    Melt In The Sun's Avatar
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    Re: Black Bottomed Gunite - HELP!

    Give it a once-over with a pressure washer and fill 'er up!
    11,200 gal, Pebble-Tec; Tristar 2-speed 1hp - Swimclear 325 ft2 cart - SWG - A & A in-floor cleaner - Heat pump. For the poolside cooking, a Yoder Wichita and a Big Steel Keg!
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    Re: Black Bottomed Gunite - HELP!

    She already had a once over with a pressure-washer......this is her after a bath.

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    Re: Black Bottomed Gunite - HELP!

    I would add some chlorine to that pressure washer and hit it agin. No need to blast it jus get chlorine on it....maybe 4:1 water to chlorine. If the chlorine helps,you will see it right away.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Re: Black Bottomed Gunite - HELP!

    OK, so we tried a 50/50 solution of muriatic acid and water and absolutely nothing happend, at all. It's the general consensus that whatever the black stuff is it isn't actually ON the pool surface, it IS the pool surface. Once again, do we paint or fill her up and live with a black-bottom pool. Will anyone swim at my house?

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    Re: Black Bottomed Gunite - HELP!

    Acid? Not sure I understand why. The stain is almost surely organic.....how about chlorine?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Black Bottomed Gunite - HELP!

    The pool guy said acid...I'll try chlorine myself. Just clorox bleach or something else?

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    Mod Squad jblizzle's Avatar
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    Re: Black Bottomed Gunite - HELP!

    Just regular old bleach ... no scented, thicker stuff.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
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    Re: Black Bottomed Gunite - HELP!

    We gave it a shot and it worked! Getting ready to give it a good scrubbing with Clorox! Just bought the t-100 test kit. Will keep you posted.

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    Re: Black Bottomed Gunite - HELP!

    So, we got the pool up and running, but at the end of the season I'll need a cover (didn't have one for three years) and the loop-loc quote I got was $3600 (NY)! Not remotely feasible. Any less expensive suggestions for my unusually shaped pool?
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    4knights's Avatar
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    Re: Black Bottomed Gunite - HELP!

    Quote Originally Posted by Bwiener
    So, we got the pool up and running, but at the end of the season I'll need a cover (didn't have one for three years) and the loop-loc quote I got was $3600 (NY)! Not remotely feasible. Any less expensive suggestions for my unusually shaped pool?
    Plenty of other mesh covers available in custom shapes for far less money.
    Mine is arctic Armour out of Canada-less than half of your quote.
    Ron- Kansas. IG fiberglass, Riviera 30 Freeform 13600 gallons,
    EasyTouch 4 w/IC20 SWCG, Pentair Whisperflo 1hp, 2 speed 220 pump, Hayward ProGrid 4820 DE filter using Eco Klean instead of DE, 2 Savi Melody 12v 5 color LEDs, Raypack 266k btu millivolt heater, Arctic Armour Mesh custom safety cover (Total self Install) TF-100 test kit w/Magic stir.

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