+ Reply to Thread
Results 1 to 5 of 5

Thread: Any alternative to acid wash?

  1. #1
    Join Date
    Jun 2006
    Posts
    17

    Default Any alternative to acid wash?

    A large number of white stains have accumulated on the bottom of our pool over its nearly 20 year life span. Since the plaster is dark blue these are rather unsightly.

    I assume the stains are due to numerous bags of calcium hypochlorite having been sprinkled around the edge of the pool over the years and further calcium deposition due to periodic high pH following poorly controlled pool chemistry. For the last year at least I have predominantly used liquid bleach and controlled the water chemistry myself, so I hope they will not get any worse.

    Three years ago the pool was acid washed. Since the pool is large (approx 30,000 gallons), the acid process was a major job and the sight of clouds of hydrogen chloride gas wafting across my yard was somewhat disconcerting. Also the job was not a great success because while some of the more unsightly stains were removed many still remained. I had not seen an acid wash performed before, so I can’t tell whether this was just an unprofessional job or the stains were particularly stubborn or acid wash was the wrong approach, but it seemed a like a lot of risk for a small return. Also emptying and refilling the pool is a major hassle (flood running down hill in neighbor’s yard during emptying and several days of refilling from well with lots of metal in water). Of course there are ways of mitigating these issues (fill from tanker etc), but I would prefer a less drastic approach if possible, even if it takes all summer.

    Any suggestions on how to identify the stains, determine what is the best way to remove them and whther it is possible to do this without draining the pool?

    Thanks

  2. #2
    mbar's Avatar
    mbar is offline Lifetime Member Whizbang Spinner mbar 3 stars mbar 3 stars mbar 3 stars mbar 3 stars
    Join Date
    Dec 1969
    Location
    Ashland, PA
    Posts
    1,009

    Default Re: Any alternative to acid wash?

    I'm sorry, but I don't know of any other way to remove calcium build up from gunite pools. I have never watched an acid wash, so I can't comment on what was right or wrong about how they did yours, hopefully someone who has had it done on their pool will chime in. It would seem to me that they would have been able to get all the stains off if it were done correctly. Anyone out there who can help????
    Northeast PA
    16'x32' kidney 16K gal IG fiberglass pool; Bleach; Hayward 200lb sand filter; Hayward pump; 24hrs; Pf200; well; summer: none; winter: mesh; ; PF:7.5

  3. #3
    mas985's Avatar
    mas985 is offline Lifetime Member Whizbang Spinner mas985 3 stars mas985 3 stars mas985 3 stars
    Join Date
    Dec 2004
    Location
    Pleasanton, CA
    Posts
    1,423

    Default Re: Any alternative to acid wash?

    Sandpaper will take off some of it but at the bottom of the pool it could take a very long time to do. You could try to get a long pole with wet paper attachment.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  4. #4
    Join Date
    Jun 2006
    Posts
    17

    Default Re: Any alternative to acid wash?

    I drained a small (1000 gallon) kiddie pool adjacent to the main pool to remove some iron stains and took the opportunity to examine the light colored stains in smaller pool. While there were a few small scale marks (easily removable by diluted muriatic acid) the more numerous light colored stains appeared, on close inspection, to be slight indentations where the lighter colored underlying concrete was showing through the darker plaster. I presume this would be the same pattern for the larger pool if I chose to empty it.

    My assumption is that the acid wash performed 3 years ago actually removed not only the scale marks but also the underlying plaster. Does this seem a plausible explanation? It is hard to know whether this was a botched job or an over vigorous wash on an ageing pool surface. Unfortunately it seems likely I will need to get the pool re-plastered if I am to get any improvements on my present situation. Any thoughts?

    On a practical note I have discovered that if I turn all the return nozzles to face upwards the rippled water surface hides the discolorations at the bottom of the pool.

  5. #5
    mbar's Avatar
    mbar is offline Lifetime Member Whizbang Spinner mbar 3 stars mbar 3 stars mbar 3 stars mbar 3 stars
    Join Date
    Dec 1969
    Location
    Ashland, PA
    Posts
    1,009

    Default Re: Any alternative to acid wash?

    I'm sorry, but I don't know alot about the plaster in the pools. Hopefully someone who has gone through an acid wash and is more familiar with the process will be able to help. Personally, I think the return jets rippling on the water sounds like a really good idea However, since you recently had it acid washed , I would look into what may have happened so that you know in case you do replaster the pool in the future.
    Northeast PA
    16'x32' kidney 16K gal IG fiberglass pool; Bleach; Hayward 200lb sand filter; Hayward pump; 24hrs; Pf200; well; summer: none; winter: mesh; ; PF:7.5

+ Reply to Thread

Similar Threads

  1. No drain acid wash
    By Myron in forum Pool Cleaning: Manual or Automatic
    Replies: 1
    Last Post: 09-18-2011, 11:56 PM
  2. Would you Acid Wash
    By topcorner in forum In-Ground Pool Construction and Repair
    Replies: 4
    Last Post: 06-12-2011, 05:29 PM
  3. Acid Wash
    By txhomebrew in forum In-Ground Pool Construction and Repair
    Replies: 4
    Last Post: 03-19-2009, 12:52 PM
  4. Acid wash new 3m plaster?
    By No Need in forum In-Ground Pool Construction and Repair
    Replies: 0
    Last Post: 04-17-2007, 07:09 PM
  5. Alternative to ascorbic acid to remove stains
    By illinipdx in forum Dealing with Stains & Metals, . . . and 'Minerals' & 'Ions',
    Replies: 9
    Last Post: 07-19-2006, 06:36 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts