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Thread: brown stains

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    brown stains

    I have a newly renovated concrete pool with a silkstone finish. I have recently noticed brown stains on the bottom. I tested the ph level and this was high. I have added some acid. Just wondered if I will be able to get .id of this as I am very disturbed in light of the fact that I have spent thousands on this pool. I will visit my pool shop this week, but wondered if anyone out there could help. Thanks. Virginia.

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    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: brown stains

    Welcome to the forum. Even though the high pH is an indicator, it's hard to say for sure what the stain is.

    High pH can often result in calcium deposits. It could also be an organic stain. Posting some pics will help and giving us a little more background like how long ago it has been resurfaced, how you are chlorinating the water, and how you have been testing your water chemistry.

    Can you post a set of current test results?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Join Date
    May 2011
    Clearwater, FL.

    Re: brown stains

    Hi happyfestifus and welcome to TFP!

    This is IMO the best site for pool problems!
    I was having a lot of trouble with my pool water and was getting run in circles with my pool store, here use this, then next weeks water sample said to try and use this now and bla bla bla! All I did was fix this weeks problem then have another one next week or 2!
    That got expensive $$ real fast over a couple of months.
    I, like you, was needing answers about pool water chemistry and found TFP though Google.
    I joined and read a lot, posted some of my questions and was greeted with lots and lots of friendly helpful advice! (really surprised me!)
    It was the advice that I got which was to get a good test kit and not use the pool store testing and do it myself.
    After much debating I ordered a TF-100 XL testing kit from Dave S. who runs
    (Thanks Dave and Meg for all you do! )
    Followed the kit instructions and used the info from here:
    to post my test #'s from my pool water testing.
    Again, I got a lot of help to fix my pool, the advice here is scientifically based and my pool did exactly what it was told to do!
    I have had a perfectly trouble free pool ever since! Always screaming for us to come swimming in it.
    This link now is also a favorite of mine to help keep this free for all the newcomers that are where I was in the beginning!

    If your looking for help, this place is a great one.
    I have a vinyl pool and I don't suffer as many problems as other pools have, but I believe that you can fix your troubles with the info found here.
    Swim n Play 21' round, expandable 72" liner, 6FT deep center, buried 14", 12,750 Gallons
    Waterway 1HP-2 speed with 22" Sand filter
    TF-100 test kit
    Thanks to TFP my pool is perfect all the time :party:
    I now suffer from Sparklypoolitis! :whoot:
    I am a Platinum contributor because I want everyone who comes here to Trouble Free Pool to have the same success that I enjoy with my pool and family.

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    Re: brown stains

    Hi, thanks for your reply. I have spoken to the pool shop people today. They said it was calcium deposit, my pool was finished back in August and has a q quartz surface. I have been advised to proceed with an acid bath, I will need to dump around 50 litres of acid to my 50,000 litre pool. I have further instructions that they have given me in regards to the procedure, I am feeling quite nervous about the whole ordeal. They have assured me that it wont damage this surface and it should clear away the calcium, ofcourse I will need to brush it. I have taken some photos, but it is very hard to see the stains. I was told that I had no chlorine in my pool at the moment, should I hold off putting chlorine in until this whole acid process is finished? What a learning curve this has for me.....lesson.....test water regularly!.....again....thanks!

  5. Back To Top    #5

    Join Date
    Jul 2011
    Arizona & California

    Re: brown stains

    Before you add all that acid, I would do as Duraleigh suggests. Post some pictures and at least provide the current pH, alkalinlity, and calcium hardness readings. Adding that much acid may do more harm than good. If there is any way to determine whether the brown areas are rough or smooth to the touch, that would also help.

  6. Back To Top    #6

    Re: brown stains

    Many thanks for your interest here. I have held off with the acid bath as strangely enough the stains seem to be getting better, I am maintaining the pH balance and plenty of brushing. I have attached my last test results but I cant attach the photos, they are too large and I dont know how to reduce the size. I have decided to not do anything drastic before at least I get a professional to come and look at it. I appreciate your comments here as I think it stopped me from acting hastily, however, now I have heaps of acid that I bought, oh well better to be safe than sorry! With gratitude, Virginia. Melbourne, Australia.
    Attached Files Attached Files

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    Join Date
    Jul 2011
    Arizona & California

    Re: brown stains

    Now that I know you didn't add the acid, I will tell you that amount of acid is way too much. It may not affect the quartz, but it will etch the cement that the plaster contains. That will just age the pool.
    Generally, if the problem is scale, then a roughness should be throughout the pool, not is just small areas. If the brown areas are small, you can do a spot test with some diluted acid, or better yet, try sanding with some 100 grit sandpaper and see if anything is removed, or the color changes.

  8. Back To Top    #8

    Join Date
    Jul 2010
    Garland, Texas

    Re: brown stains

    If it's of any help at all, I battled with brown stains appearing here and there for many months. Eventually I figured out the cause which was either too high pH or too low alkalinity, or both. In other words, if my water balance was too far out of whack, brown stains (that look a bit like rust) appear on the concrete finish. I have some now, as a matter of fact, because it has been raining for a couple of days here. I tested my water and my alkalinity was way low. I have added some Baking Soda and if past experience is anything to go by, the stains will be gone within 24 hours. If the problem is too high pH, then add Muriatic Acid to bring it down.

    I've attached a couple of photos of what my brown stains typically look like in case yours are the same.
    Attached Images Attached Images

  9. Back To Top    #9

    Re: brown stains

    Thanks for the photos, my stains were not quite as dark as those but similar, the stains have totally disappeared and yes, they did appear after a lot of rain over a few days. I am just so happy right now about it, and so glad I didn't do the acid bath, I returned the three tubs of acid and the 25 kilos of buffer. I appreciate your feedback and I am slowly learning. My lesson here is to always get my water tested and never assume if it looks good it must be ok, thanks again!!

  10. Back To Top    #10
    Ohm_Boy's Avatar
    Join Date
    May 2007
    Orlando, FL

    Re: brown stains

    My lesson here is to always get my water tested ...
    The best lesson would be to learn to test it well yourself. You're more likely to be meticulous and accurate, and your results will be more repeatable. Get a quality test kit, one which includes a FAS-DPD chlorine test, and take control. You'll never look back.
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

  11. Back To Top    #11

    Re: brown stains

    Thanks to you all, I don't feel so alone with all this now!!

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