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Thread: Crystals on the walls and floor of my pool

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    Crystals on the walls and floor of my pool

    We bought a house with an inground plaster pool. We removed the cover today and drained the pool. There are crystals growing all over the pool walls and floor. I am a newbie at this so I have a lot of questions. I can remove the crystals with a scraper--have tried that and it works. If I use the power washer, it takes some of them off but not all of them. This is a chlorine pool, not a salt water pool.

    1) How can I remove the crystals?

    2) What causes crystals to form? The crystals are thicker toward the top
    of the pool--about the top 3 feet. They are brown but when I powerwashed areas, it appears to make the brown go away and leaves some of the crystals.

    Any and all help is most appreciated!

    Jody
    6,000 gal. IG FG pool Sta-Rite max-e-pro 3/4hp
    Sta-Rite system 2 cart. filter
    Sta-Rite 200k BTU heater
    Tiger River Bengal spa

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    Join Date
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    Welcome to TFP!

    In order to help you out, we will need some test results. It's important that you get yourself a good test kit. A good test kit will save you so much trouble and money in the long run. It is the best investment that you can make for your pool. Either the TF100 at www.tftestkits.com or the Taylor K-2006. In the meantime, take a pool water sample to a pool store and get it tested. It won't cost you anything to do so. The pool store employee will probably try to sell you something. Don't buy anything yet. Just bring the test results back to this site and post them. You will get solid advice that you can trust right here.


    I just realized that you said that you drained your pool. The experts will be by shortly to add their advice but one must be very careful when draining a pool completely as damage can result when doing so. I would still go ahead and get yourself a test kit.

    Craig
    10K gallon IG gunite with waterfall; Pentair CC320P filter; WhisperFlo 2 HP pump
    TF Test Kits - Pool Math - Pool School
    "It depends."- JohnT

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    JasonLion's Avatar
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    A picture would help.
    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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    Photos of Crystals

    The crystals are dried this morning and some can be scraped off with my fingernail. Others are stuck tight!
    Attached Images Attached Images
    6,000 gal. IG FG pool Sta-Rite max-e-pro 3/4hp
    Sta-Rite system 2 cart. filter
    Sta-Rite 200k BTU heater
    Tiger River Bengal spa

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    Join Date
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    Calcium?
    10K gallon IG gunite with waterfall; Pentair CC320P filter; WhisperFlo 2 HP pump
    TF Test Kits - Pool Math - Pool School
    "It depends."- JohnT

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    I am so new to this forgive me if I am asking a dumb question, but how do I tell if it is calcium?
    6,000 gal. IG FG pool Sta-Rite max-e-pro 3/4hp
    Sta-Rite system 2 cart. filter
    Sta-Rite 200k BTU heater
    Tiger River Bengal spa

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    Hi, Jody,

    Well, that's a pretty unique problem. I can only guess that something (or many somethings) were put in your pool that shouldn't have been.

    Then your pH probably got w-a-a-y to high and whatever that stuff is precipitated out onto the pool walls. It doesn't sound like calcium deposits (scale) Normally scale is quite difficult to remove....from your description, it comes off the walls easier than calcium.

    Here's my thoughts.....and keep in mind it's only speculation 'cause I don't know what those deposits are:


    1. A professional acid wash may be the best bet.

    2. I'm not sure a power washer is a real good idea....you could easily damage the thin layer of plaster

    3. You could try refilling your pool and keeping your pH around 6.8 (very carefully)...that may very well dissolve the deposits but it may take weeks.

    Keep us posted. I've never seen it before and will be curious find out what it is.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Crystal deposits

    Some information about the water might help you too--Rockdale, Texas water has iron suspended in it and is hard. It appears that someone threw chlorine tablets in the bottom of the pool. You can see the outline of 3 inch circles on the floor of the pool. Those areas are the only ones without crystals on them... Does that help any?

    Jody
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    6,000 gal. IG FG pool Sta-Rite max-e-pro 3/4hp
    Sta-Rite system 2 cart. filter
    Sta-Rite 200k BTU heater
    Tiger River Bengal spa

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    Guest
    Very possibly calcium nodules. http://www.poolhelp.com/onBalanceCalciu ... lletin.pdf
    The fact that the low pH trichlor tablets removed them indicate an acid wash is going to help since the low pH (about 2) of the thrichlor that was sitting on the pool surface removed them.
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    Quote Originally Posted by waterbear
    Very possibly calcium nodules. http://www.poolhelp.com/onBalanceCalciu ... lletin.pdf
    The fact that the low pH trichlor tablets removed them indicate an acid wash is going to help since the low pH (about 2) of the thrichlor that was sitting on the pool surface removed them.
    Would make sense being that this pool is located near Rockdale. Water is VERY hard there as the poster stated. Lots of limestone around there.
    10K gallon IG gunite with waterfall; Pentair CC320P filter; WhisperFlo 2 HP pump
    TF Test Kits - Pool Math - Pool School
    "It depends."- JohnT

  11. Back To Top    #11
    I read the article on calcium nodules. What I understand is that we may need to replaster or is that just in the worst case scenario? I am going to the pool supply store in Round Rock to get acid wash and try it.
    6,000 gal. IG FG pool Sta-Rite max-e-pro 3/4hp
    Sta-Rite system 2 cart. filter
    Sta-Rite 200k BTU heater
    Tiger River Bengal spa

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    Jody,

    Acid washing is a process, not a particular chemical.

    Unless you have worked with acids before, undertake that process with caution....most people leave that to folks who do it for a living. That said, it can be done but I would not try it.
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    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  13. Back To Top    #13

    Crystals

    Dave,

    Thank you! I am learning. I am waiting on a pool expert to look at the pool and tell me about acid washing. Getting lots of advice and I am so appreciative!

    Have a great Memorial Day,

    Jody
    6,000 gal. IG FG pool Sta-Rite max-e-pro 3/4hp
    Sta-Rite system 2 cart. filter
    Sta-Rite 200k BTU heater
    Tiger River Bengal spa

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    Test Results

    Here are my test results. The only one that I am not confident of is the Cyan:

    FC 4.5
    PH 7.2
    TA 90
    CYA 20
    Calcium 200

    I have been brushing the pool daily with the wire brush and running the filter about 8 hours a day. The crystals are less but they are still SHARP and my feet hurt if I spend much time walking around.

    I talked to the previous owners and learned:

    They used test strips. They never added anything last year except for chlorine tablets. She said that the chlorine never tested high enough and that they had up to 19 3" tablets in the pool at one time. They did nothing to winterize except clean out the powder in the filter and drained the pump and filter. She said that the steps were the only part of the pool that tended to grow brown kind of "stuff" on them...

    So, the crystals we have scraped off look like sand. We have tried to get them to disolved in liquid bleach. That didn't work.

    Any suggestions?

    Jody
    6,000 gal. IG FG pool Sta-Rite max-e-pro 3/4hp
    Sta-Rite system 2 cart. filter
    Sta-Rite 200k BTU heater
    Tiger River Bengal spa

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    JasonLion's Avatar
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    Have you tried getting a crystal outside of the pool and putting a drop of muriatic acid on it? If it is some form of calcium it will bubble and foam.
    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

  16. Back To Top    #16

    Re: Crystals on the walls and floor of my pool

    I had similar problem and HCl acid solved this.

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