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Thread: CL stains on Calcium on Limestone Raised Beam!!

  1. Back To Top    #1

    Join Date
    Feb 2008
    Location
    Dripping Springs, TX
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    79

    CL stains on Calcium on Limestone Raised Beam!!

    Hey folks - I had a pool built about 15 months ago and it has been going great except I've started to notice what I believe to be Chlorine stains on the limestone surface of my raised beam.

    I'm pretty confident it is a stain and chemical related because I've sprayed it with a 50/50 Bleach/Water mix and it doesn't go away like algae does (I've done this before and I know what algae looks like).

    Now obviously my waterfalls aren't 100% perfect and so water is running down some of this limestone. Limestone is porous in general and I asked my PB about this when I was choosing stone, but he assured me "the limestone is from the best quarry around and it is super dense". It matches my house (all white limestone block) so that is why I chose it inially. In hindsight I wish I chose some auqua/torquoise colored stone and tile... GEEZ!!

    I also have a lot of calcium showing on my stone/tile and even down into the plaster area. I'm confident this is coming from the limestone wall above and the constant water being washed down parts of it. The calcium is also showing stains in a few spots but luckily with a crow bar or pick I can easily knock that off in chunks so it is not too bad. I get a lot of calcium buildup on the tile (well I did in the course of a year) which I also was able to get mostly off but you can see remnants are still there - it's impossible to get it all off - I even tried the suggestion of a forum member here, to use a circular wire brush buffing bit in my power drill - that was impossible to hold still and didn't really help - the crowbar is the only tool out of like 10 I have tried including the drill/brush, steel wool (too yucky), sponges, a handled wire brush, and more...

    I was also told the calcium would be made by the plaster, but I don't think that is what is causing this. I think that will be IN my pool only and at the bottom of my gray plaster I do have some spritzes of white calcium stuck on the floor here and there. They kind of look like little sunburst and actually look OK so I don't even really mind that at all.






    What do YOU all think (I should do to resolve this)??

    Some other pics of my pool:




    Thanks for reading, let me know what you think I can do!

  2. Back To Top    #2

    Join Date
    Jan 2009
    Location
    Cupertino, CA
    Posts
    1,966

    Re: CL stains on Calcium on Limestone Raised Beam!!

    That is one gorgeous pool area.

    Oh... what you should do... right... What you should do is post a full set of test results so we can figure out what's going on with your water.
    --paulr
    BBB "Intermediate Swimmer"
    IG plaster pool 18.5K gal, Hayward Pro-Grid DE filter, 3/4 HP Hydramax II; Polaris 380, 3/4 HP booster
    AG spa 325 gal, probably Sundance of some kind
    Water testing instructions on one page

  3. Back To Top    #3

    Join Date
    Feb 2008
    Location
    Flower Mound, TX
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    5,062

    Re: CL stains on Calcium on Limestone Raised Beam!!

    Looks like efflorescence to me and it is a result of chemicals (calcium for one) leaching out from the masonry when exposed to moisture. I have had the same thing deposit on my stone and tile from the mortar beneath my waterfall.

    I cleaned it up fairly easily with a dilute acid and water mixture. A 25:1 water to HCl solution applied with a long brush so that you don't get the mixture on yourself in the process should work to take it off of there. Be sure to rinse the area well once you are done as you don't want the solution to remain on there any longer than you have to.
    10K gallon IG gunite with waterfall; Pentair CC320P filter; WhisperFlo 2 HP pump
    TF Test Kits - Pool Math - Pool School
    "It depends."- JohnT

  4. Back To Top    #4

    Join Date
    Feb 2008
    Location
    Dripping Springs, TX
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    79

    Re: CL stains on Calcium on Limestone Raised Beam!!

    257WeatherbyMagnum thank you so much for that idea!! I agree with your analysis of what is causing it. I was thining it is Calcium buildup but maybe it is Efflorescence indeed. It crumbles like it when I mess with it. It is mostly whiteish, but now it is getting stained I believe - green and blue probably from the chemical reaction but also it could be from two brands of CL I've been using?

    I don't think it will ever stop either, which worries me. And maybe I need to find a way to prevent my waterfall+scupper from dripping around the edges?? I fear that won't ever be possible at least with my scupper.

    To get it off, should I use Muriatic acid or Hydrochloric? And if the latter, where can I get it?

    And what kind of brush? My pool brush or a metal brush? *gasp*

    I think I'd prefer to SPRAY it on with a little plastic water sprayer I have which I use for CL+Water sometimes on algae spots - but will this be OK with the M or HCl acid?

    Thanks!

  5. Back To Top    #5

    Re: CL stains on Calcium on Limestone Raised Beam!!

    Quote Originally Posted by IPvFletch


    To get it off, should I use Muriatic acid or Hydrochloric? And if the latter, where can I get it?
    !
    Its the same thing. Hardware store or a big box store will have it.

  6. Back To Top    #6

    Join Date
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    Re: CL stains on Calcium on Limestone Raised Beam!!

    No problem . Therein lies the purpose of this fantastic forum!

    As Brad S mentioned, hydrochloric acid and muriatic acid are the same thing, the latter being an antiquated but still often used (by me as well) name for it. I get mine at Home Depot. There are two one-gallon bottles in a box for about $10, plus or minus.

    Just take a bucket, add the water first, and then the acid. The way I brushed it on mine was by using a plastic brush with plastic bristles. I actually used a dishwashing scrubber brush and affixed it to a long wooden dowel with duct tape. Duct tape fixes everything you know . This way, I could reach further and be well away from any splatter. Muriatic acid is some nasty stuff and you don't want any of it on you, even in dilute concentrations like this. Make sure there is no metal in your brush or you'll dissolve your brush before you rid yourself of the deposits.

    Make sure that you rinse the surfaces between applications and rinse well when you are finished. Not doing so can cause damage to things.

    You may notice that despite your best efforts, efflorescence can return. Mine does. Just keep up with it and make sure that your water balance stays in check.
    10K gallon IG gunite with waterfall; Pentair CC320P filter; WhisperFlo 2 HP pump
    TF Test Kits - Pool Math - Pool School
    "It depends."- JohnT

  7. Back To Top    #7

    Join Date
    Feb 2008
    Location
    Dripping Springs, TX
    Posts
    79

    Re: CL stains on Calcium on Limestone Raised Beam!!

    Ok, I did not realize they are the same thing. I never knew Muriatic was HCL. Duh!

    Fortunately I do have some Muriatic acid and have used it before to break in my pool and get it balanced initially and also once to remove a stain from my limestone coping, so I should have put 2 and 2 together and figured this would work.

    So don't use Metal (like metal bristle brush) with HCL, right?

    Thanks all!

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