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Thread: A Possible Mistake in Adding Calcium

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    Join Date
    Jul 2011
    Location
    Austin, TX
    Posts
    60

    A Possible Mistake in Adding Calcium

    I am just finishing up my pool preparing for the season, and my last step was to raise the calcium level (I just did a drain and refill).

    The instructions say not to premix in water, and to cast over pool. I have a dark bottom pool and now there are white/light spots where the calcium carbonate landed. I quickly hit it with the brush, but it did nothing. There was even some that landed on the main returns on the bottom, and they have a white ring on them.

    Will this go away? Or did I just permanently etch/stain the pool bottom??

    FC=3
    CC=0
    pH=7.5
    TA=110
    CA=40
    CH=175 (moving it up to 250)
    16,000g in-ground plaster pool, attached spa, BBB, DE Filter, SWG

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    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: A Possible Mistake in Adding Calcium

    It should continue to dissolve until it is all gone. However, I haven't heard of it sticking to the bottom before, so I am not completely sure what is going on.
    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: A Possible Mistake in Adding Calcium

    When the water is cold, calcium chloride can stick to vinyl, plaster or fiberglass. It can also form hard clumps.

    I don't know why this happens much more when the water is cold. I premix and pour to prevent this.

    Premixing can be a problem due to the heat generated by the dissolving calcium chloride. However, as long as you're careful to use plenty of water and mix well, it shouldn't be a problem.

    If you don't want to premix, then it's best to have the brush ready to go as soon as the calcium chloride hits the floor.

    For your current situation, keep brushing to help speed the dissolution of the calcium chloride.

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    gtemkin's Avatar
    Join Date
    Jun 2008
    Location
    Seattle, WA
    Posts
    738

    Re: A Possible Mistake in Adding Calcium

    You said it was Calcium Carbonate that you added but most of the Calcium up products I've seen in pool stores is Calcium Chloride. Can you verify which it is?
    21K gal 16' x 40' in-ground pool built 1959, old school with Jacuzzi bronze pump, American Products 24" Sand Filter & Americana Multiport valve, Jandy Lite2 millivolt heater, Coverstar cover, and classic Kreepy Krauly.

  5. Back To Top    #5

    Join Date
    Jul 2011
    Location
    Austin, TX
    Posts
    60

    Re: A Possible Mistake in Adding Calcium

    You are correct. Calcium chloride.

    I checked this morning and the marking/etching is still visible. Some of it is dissipating. I'll just keep brushing and hope that it dissolves over time... It's mostly frustrating because I just drained it to clean it and it looked awesome!

    BTW - Turned off SWG and going BBB (bleach). So far, so good. SWG in combination with the heat here in Austin, TX and water creates high pH, which in turn caused calcium buildup / stain. I'm actually adding about the same amount of bleach as I was acid, and it's 1/5 the cost. I can always add the salt and turn it back on, but it's hard to pull the salt out!
    16,000g in-ground plaster pool, attached spa, BBB, DE Filter, SWG

  6. Back To Top    #6
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: A Possible Mistake in Adding Calcium

    If you balance your levels correctly you can run a SWG with minimal acid additions. You will most likely still need a little acid, but it shouldn't be anything like the volume of bleach the pool requires.
    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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